What are needed skills and usefull feats/traits to have in this adventure path? I'm playing a Tiefling Rogue made with 25 point buy.
The AP has a lot of possible social interactions, so anything face-related can be great, but that also depends on your group: if they are hack-n-slay, don't bother.
Much of the AP is based in and around cities, so anything city-related is good. I feel nature-freaks are going to miss the wilderness quickly, so for rangers I suggest urban rangers or similar, and I'd avoid druids. But you can certainly try anyways, just don't expect your DM to change the module, to have you get your wilderness-fix. ;-)
Hmm so a thug type Tiefling Rogue wouldnt be good?
Well, you asked what skills/traits... I told you social stuff is good.
Do you intend to go all out intimidation? Could work, just realize that some people (NPC) might try to pay you back... and they have the needed acquaintances to do so.
You'll stay in the same cities for quite a while, too. The key is to befriend the right people. ;-)
But then, somebody else could take on the role of nice guy and you could do the nice officer, bad officer routine...?