See guys. They know who to turn to when it comes to stuff like this.
As Harlock was kind of point out Scarred Lands Halfling are pretty down trodden lot. My advice, make them a lot like Scots/Irish/Welsh in terms of outlook. They have gods (or a racial god as often the case.) They believe heavily in having their own homeland and free of outside influence. They are very much nature oriented but not so much they can't adapt other places. Most of the time, Scarred Lands Halflings tend to adopt the traits and attitudes of those around them. But others, such as halfling rebels, often go around starting fights and trying to prove themselves as capable even when others don't see them that way. At best they get along better with elves than most, since there's a long racial history of wood elves and halflings from the days of the Ganjus. As for being a halfling rogue, be shifty. Don't trust easily but always appear merry. It keeps the other guys off their toes. Enjoy mead and ale. And if you are female, don't mind the friendly advances outside your race. Just make sure the men understand you're in charge when it comes to your body. Overall I suggest acting like a brass Scottish/Irish/Welsh lass of lore, keep your crowsbow/sling/what ever ranged weapon you have handy, and always make sure you know whom you are dealing with.
Hope that helps.