Skyshards are scattered throughout Tamriel and can be found in every zone in the game. They are located in dungeons, explorable caves, and regular overland areas with 16 Skyshards per zone (With the exception of Bal Foyen, Betnikh, Stros M'kai, Bleakrock Isle and Khenarthi's Roost).
Skyshards can be identified at a distance by their tall, bright beams of Magicka emanating from them. Because of this, they can be seen over small rock formations and hills. They also emit a low humming sound when one is nearby.
In total, there are 339 Skyshards in the game. This means that 113 skill points can be gained from Skyshards alone.
All the hints, also displayed in the in-game achievements tab, are given below.
Many sites and databases also have interactive maps with all of the Skyshard locations in detail. A Google search can give you a lot, if you don't want to look for them yourself. 
These sites have all of the Skyshard locations:
Aldmeri Dominion Territory
Khenarthi Roost (6)
- Exposed to sky, surveying the strand.
- Southern temple's hidden jewel.
- Along the inlet through the moon.
- Abandoned before mourning.
- Sighted by serpents in Mistral.
- Surly root-chewers borrow nearby.
- A landing of noble's blood.
- Adorns Valano's terrace.
- Offered to appease riled ancestors.
- Watching the sky in a tower of swords.
- Between cursed ruin and shrine.
- Near Merormo's refreshment.
- Contemplation's overlook.
- Up and west in the broken dawn.
- Gleaming beacon, ship-guide. (Lighthouse)
- Ancient chamber of golden glow.
- The Heritance stakes this claim.
- Near the folly's end.
- Held in a corner by the House of Troubles
- Blood-drained Thralls stumble past.
- Corpses from another age walk here.
- Hidden home in the gully's wall.
- Granted safe haven by the mages.
- The shrine of the south leads north.
- Cooling off on the wat to the Tower.
- Where the road to the root is in isle.
- Atop falls that feed the temple.
- Spotted from a treehouse vantage.
- A doorway to trolls near Redfur.
- Among ancient words in the stones.
- Above a seasonal site of return.
- Where Covenant forces pour forth.
- A scrabbling, a skittering, a scurrying.
- Six-legged thunder invades.
- Not yet dead on the vine.
- Stolen starlight in wormy depths.
- Mined by the bandits of Mobar.
- Crocs claimed a meal in the sunder.
- Flee the labyrinth of words and stone.
- In crumbled keep where shadows creeps.
- Breath of fresh air for Marbruk's mages.
- Find and eclectic outskirt by the sear.
- Where moor becomes moat.
- Stay dry where the wooded Eye wards.
- No longer entrenched.
- Unheeded by Wood Orc lookouts.
- Down in the gorge of rope bridges.
- In Gurzag's supplies.
- Halls ruined further by blue-skin brutes.
- A pretender in Naril Nagaia.
- Under root, but hidden high.
- Batted around the purring lair.
- Minded up in a barrow.
- Outside the Harbinger's chamber.
Malabal Tor (16)
- On an orbit of the storm sphere's home.
- The best view of Fuller's Break.
- Unnoticed by a melancholy Elf.
- Near the river, disentangled.
- Seek seaward cliffs by the brewery town.
- Fell from a bridge fleeing Abamath.
- Search every nook of lift to Vale.
- Eyed from a islet in the river.
- Follow the sound of wilding waves.
- Withered within the vine.
- Dropped off when he still lived.
- Property of parasites.
- Fungus dwellers dig, far from home.
- Part of Array's spectral dominion.
- Haunted by heretics.
- Held by red-handed bandits.
Reaper's March (16)
- East from the solemn eye's shrine.
- Where temple became tree-house.
- In a smoldering shell.
- Overlooking the site of the fall.
- Camped on the way to Claw's Strike.
- Hidden by less subtle blade.
- Dune's arcane beacon.
- Mara's devout frets in view.
- Within earshot of the cheering crowd.
- Growling, beastly gladiators prowl.
- Treasure of the bard's tomb.
- Awash in tears underground.
- Outlaws strike skooma deals here.
- The folly is in passing through quickly.
- Moon's light reveals its secrets.
- Far beneath a foul manor.
Daggerfall Covenant Territory
Stros M'Kai (3)
- Across the water from the western wall.
- The mouth of The Grave stands open.
- Crashed through a Saintsport roof.
- To the left of the Central Crypt at Moriseli.
- Northeast of Carved Hills.
- To the left of the main crypt in grimfield
- Guarding Daggerfall's eastern gates.
- Before Dresan's Headless sentinel.
- Search amongst the shrieks.
- Westtry's dead slept underneath.
- Far behind the Elf-haters' lines.
- Beneath a Hag's footbridge.
- Where vines strangle of sleeping dead.
- Close to finding the kings.
- A climb above crosswych.
- A tower explored is llessen learned.
- Near silumm's wall on Daggerfall shores.
- Within a mine of blood and thorns.
- Behind a wall of Enduum all.
- Where Ebon Crypts become Ebon Caves.
- In the bowels of Cryptwatch.
- In the roots of the Hallows.
- On Koeglin's crown.
- Atop of stairs of Newgate.
- Beside the henge of Nightmare Crag.
- The foot of Wind Keep's falls.
- Before a breach in Aphren's wall.
- Atop the soulless tower.
- In a monster's pantry.
- Where the giant's tears fall.
- Camped in sight of the eastern gate.
- Delve deep with the bear's claw.
- Locked behind Farangel's iron bars.
- Mine your manners outside Steelheart.
- Explore the ruins north of Wind's Keep.
- Comb the abbey's catacombs.
- West of firebreand, deep beneath the tower.
- Explore the ruins of broken marrow.
- Just outside Shornhelm's gate.
- Honoring the dead in Eyebright's west.
- Crumbled tower, Crestshade's welcome.
- Wolves howl at the Hoarfrost nearby.
- Cresting the wood of words.
- High in the debris of the hills.
- Skittered over in the pass.
- Follow the song to the Landing.
- Ditched outside of Lorkrata.
- In the tunnels under Cresthade.
- Seek worksm who burrow for a tear.
- Among Flyleaf's unearted dead.
- Secret in the blood-suckers' hideaway.
- Look upon the Orsimer's Hand.
- Conquer the crypt of trials.
- Stolen by worshupers of Ashpit's Lord.
Alik'r Desert (16)
- Sentinel of a doomed tower
- Shedding shame in the oasis
- Across the ruin from the Warrior.
- Stored on a Bergama roof
- Walltop view of the broken blade
- Beside a drydocked stern.
- Left out in the open by Kozanset Mages.
- Near a paid feather-finder
- Tears shed for a toppled spire.
- Second stop on her search for the Pearl
- Buried respite from desert heat.
- Dig deep, don't be embarrassed.
- Blown down a mine shaft.
- A caravan's wreckage marks the path.
- Trapped within the steam closet
- Monumental find in the Lost City.
- A scenic view of evermore's bridge.
- Listening to Silaseli's whispers.
- Tossed into a coveside tower.
- Answer the call of battle.
- Secret shrine of Pelin's Church.
- Hears hags but sees mobile limbs.
- Waiting to be inducted to the Hall.
- Take a fall from the grotto.
- Nested in an Imperail camp.
- Sent away to stay with the dead.
- Tragic tale of architect and princess.
- Found in spite.
- Where a stormy ritual brews.
- Stuck in a troll's maw.
- Bjoulsae bandits' hidden lair.
- Beddling Imperaisl disrupts the wheel.
Ebonheart Pact Territory
Bleackrock Isle (3)
- High atop the shrouded Barrow. (Skyshroud Barrow)
- A Hollow victory beyond the iceflows.
- To dig too deep would be no Folly.
Bal Foyen (3)
- Hidden near the highest hut.
- In the fort, just around the way.
- About to set sail.
- Watching lions swim to shore.
- Near Bal Foten's gate.
- Staging an attack on Arand.
- A lady on a cliff, beyond Sulfur Pools.
- Among mushrooms, high above Lukiul Uxith.
- Among pools of fire, above Vivec's Wayshrine.
- South on the Ashen road, where lava flows.
- Tucked away, on a grotto's mantel.
- On a hillside behind a plantation.
- Left to rust beside the ancient arms.
- Used to strike flames underground.
- Listening to the Spinner's whispers.
- Found in soft dirt by daggers.
- Where fiery tide rises.
- Discovering a taste for madness.
- Drowned in the south by a clever bird.
- Free from quarantine.
- A Hlaalu victory in Narsis.
- A river view on Muth Gnarr's outskirts.
- A twin falls in Mournhold.
- Near the remnants of a House caravan.
- Follow the river that snakes south to its source.
- Search near the cavern with three yese.
- The right tower is Tal'Deic's left.
- WHere ships dock and mushromes Mire.
- Where the dead walk, no memories linger.
- Lend me your ear.
- Where a ladt seeks kwama before the storm.
- Asleep in the depths, the Dwemer awakens.
- Mine your step where the water drops in.
- Go from Crags to riches.
- Where corpses till a garden of Sand.
- Above the Mages' eye between the falls.
- Still shrouded by spray past a western rise.
- Sneak behind the relic-thieves' camp.
- Beside a bowsprit among pirates.
- Ritual flames brew trouble in the mire.
- Where wisps waylay wanderers.
- Like the sound of steam or snakes.
- Overlooking the murk of Xal Ithix.
- Imprisoned in a crumbling tower.
- Peek behind pillars in Atanaz.
- Skittering, slithering, a tusk once whole.
- Uneartedh by an outload excavation.
- Crpwn in hand, leave the look right.
- Climb little kwama, to reach your goal.
- Digesting in the belly of the Black Maw.
- Deep in the den of deauchery.
- Nestled beside Morvunskar's royal tomb.
- Giants despoil the village below.
- Leave the hollow to cure the chill.
- Strean between tusks near the barrow.
- Beside a bridge of Amol.
- List in ruins beyond the grotto.
- Mzulft's secrets are not all underground.
- Attempt to spy on Aelif.
- Stashed near a farm in icy winds.
- An illegitimate child's reading materials.
- Search the slipperiest places in the hollow.
- Three eyes gleam, a frigid prize.
- crashed from the sky to open the vault.
- Old Sord excelled at hide-and-seek.
- Among the dead, sheltered from storms.
- Near a throne in the Hall of the Dead.
The Rift (16)
- Braced against wind near the mine.
- Be Shor to search all over the stone.
- Nearly discovered by a mauled stablehand.
- Cultists' prize near Ragged Hills.
- Scour the crags near Avancheznel.
- South where worms swarm the barrow.
- A prospect found.
- Walk above the clouds.
- Stay alert between Riften and Greenwall.
- Clank of Gears and hiss of steam.
- Guarded by bears in the hollow.
- Deep in the roots of the tooth.
- Where green grows in the fort's wall.
- Take a shrouded approach.
- Tread carefully; don't break a leg.
- Protected by wraiths in a beast's den.
Coldharbour Locations (16)
- East of the bastion of deciet.
- Discarded from the mages' walls
- Seek a shattered bridge suspended
- Unfit for court.
- Ejected from the Village
- Among the vessel's burnt cousins
- In the Chasm's western watchtower
- Not invited into the plotting wives' home.
- Washed to strange shores with the fleet.
- Among the bones of Aba-Loria
- Enduring Forgefire's flames
- Seek the deepest depravity
- Entombed in the Orchard
- One of the hunter's many prides.
- Where endless cries issue forth
- Behind disaster-claimed Dunmer hall.
Aldmeri Dominion Territory (15)
- Within sight of Mnem.
- Ascending toward prophecy and dawn.
- Helping establish a new town.
- Tooth of Jone or Jode.
- Ruined spire peering north to the Tower.
- Hears hacking in the east.
- Upon timbered fingers.
- Ruin's crown between three castles.
- Where archers of the Eight train.
- Six-legged assassins crawl the cave.
- The Black Dagger's prize.
- Singing straw's song.
- Walk the Shadowed Path
- At the end of a bumpy road.
- Where bear and ogre burrow.
Daggerfall Covenant Territory (15)
- Approach the southern scroll.
- Overlooking Ni-Mokh's falls.
- Near liquid fire flowing.
- Decorating a Nord's manor grounds.
- Offering at the priory.
- Atop a crumbling Empire.
- Home of the goat-faced altar.
- Search near the cliffs... cliffs... cliffs...
- Where a ruin-seeking Khajiit is denied.
- Bandit's crowning achievement
- Amid reverberations of clattering bones.
- Vampires prowl where Elves once lived.
- In a cave of crimson treasures
- Surrounded by frozen fungus.
- Under shroud and ground.
Ebonheart Pact Territory (15)
- Near the scroll of royalty's secret syllable.
- Rope ladder hangs south of Ghartok.
- Keeping the crops alive.
- Cradled in a ruined temple hall.
- The Arvinas' pride.
- Blue Road's trees fall just down the hill.
- Where bound spirits hold vigil.
- Soft wings spin choral garb.
- Wedged well in Sedor.
- Fractured by the Bloody Hand.
- The monarch's buried secret.
- Enjoy a good roll in the much.
- Nurtured by amphibous host.
- Rushing water in the depths.
- Facing the Faceless.
Cyrodiil: Other (1)
- Find the Skyshard on top of the mountain in Cyrodiil.
- ↑ August 2, 2013. Twitch.TV QuakeCon, Day 2: The Elder Scrolls Online, John Carmack, and more!
- ↑ January 25, 2014. ESO Schatzsucher. Live Q and A mit Kai Schober Und Rich Lambert - Page 7
- ↑ March 23 2014. Dulfy.net amongst some of the guides out there