After talking to the shop owner talk to the droid again and the droid should ask you to help find a missing droid. Talk to the droid and then talk to the shop owner. Next go through the door into the Swoop Garage and follow the hallway right. Give him the Credits for Light Side Points.
Keep going and approach the first door you see to trigger a man asking you for credits to help him. Make sure you talk to him again after the fight too. Just up the walkway you will encounter some exchange thugs picking on a man. Pay the docking fee to end that conversation. When you first land on Nar Shaddaa you will be approached.
Atton can be turned into a Jedi very quickly on Nar Shaddaa and there are several opportunities to gain influence with Bao-Dur in the early parts of Nar Shaddaa. Suggested Starting Party: When you play Nar Shaddaa I highly recommend that you take Atton and Bao-Dur with you first through the first series of quests on Nar Shaddaa.
I guess the whole point here is that this will be a very LONG guide that might look overwhelming at first. Nar Shaddaa also probably has the most fighting out of all of the planets you visit. It also involves a LOT of character/party swapping at different points. WARNING: Nar Shaddaa is by far the LONGEST planet in Knights of the Old Republic 2: The Sith Lords.