Taking Care of Business

This is the second quest pertaining to the Thieves Guild, acquired from Brynjolf.

Objectives

 * Locate Brynjolf at the Ragged Flagon
 * Collect Keerava's debt
 * Collect Bersi Honey-Hand's debt
 * Collect Haelga's debt
 * Return to Brynjolf

Walkthrough

 * Find the door to the Ratways, located on the lower levels of Riften.
 * In the Ratways, there will be a couple of aggressive bandits, named Drahff and Hewnon Black-Skeever, who will need to be aggressively dealt with.
 * Soon after, drop down to the lower level and destroy the Skeever as well.
 * Now either pick the lock (Expert) on the door to the left or take the path to the right.
 * Shortly, the entrance to the Ragged Flagon can be detected and find Brynjolf at the bar.
 * He will instruct the Dragonborn to collect debts from three business owners in town. Exit the Ragged Flagon by the front door, then go through the second archway on the right wall. Pull the lever to drop the draw bridge across the gap and follow the path to exit the Ratways.
 * Whatever order the debts are collected in, the third target will have heard about the previous two and chooses to simply hand over the money when spoken with about it.

There are a few different ways to get the money.

Keerava's debt (in The Bee and Barb)

 * 1) Speak first to Talen-Jei, a male Argonian. Talen-Jei is likely just inside the door, or upstairs sleeping in his room. Choose the dialog option about talking some sense into Keerava. Then speak with Keerava about giving Brynjolf to convince her to pay the dragonborn.
 * 2) Alternatively, choose to brawl with Keerava. Win the fight and she'll pay. Accidentally hitting another patron during the fight will give a bounty, and cause Keerava and everybody else to be hostile.
 * 3) Kill Keerava and loot the 100 gold, but Brynjolf will not be happy about this.

Bersi Honey-Hand 's debt (in The Pawned Prawn)

 * 1) With a weapon, attack the urn until it is destroyed in front of him. Then speak with him and he'll pay.
 * 2) Additionally, challenge him to a brawl. Beat him into submission and he will pay.
 * 3) Kill him and loot the 100 gold, but Brynjolf will not be happy about this.
 * 4) If you have collected the other two debts he will just give the money to you.

Haelga's debt (in Haelga's Bunkhouse)

 * 1) Around the corner from her counter is the statue. Be sure to sneak first to avoid a bounty, and steal the statue. Then speak with her to receive the debt payment.
 * 2) Brawl with her and she'll hand over the money when defeated.
 * 3) The dragonborn can kill Haelga and loot the 100 gold, but Brynjolf will not be happy about this.
 * 4) Talk to Haelga but do not loot the statue, brawl or kill her. Then collect debts from Keerava and Bersi Honey-Hand  (After brawling with Bersi), tell Haelga you have a message from Brynjolf and she will instantly pay up.

Once the debts have been collected, return to Brynjolf in the The Ragged Flagon. He will invite the Dragonborn to walk with him. Mercer Frey will give the follow up quest Loud and Clear and welcomes the dragonborn to the guild.

Rewards
After completing the quest and accepting the follow up, "Loud and Clear", a few perks are gained:
 * Membership into the guild.
 * Speak with Tonilia in the Ragged Flagon to receive the Thieves Guild Armor.
 * Tonilia becomes available as a Fence.