Definitely fold ATo like other posters have said, call with ATs. I would raise with AJs or KQs.

About AJo and KQo. Under the gun I really dont think it matters in the long run whether you raise, call or fold these hands. These are probably the two most popular borderline hands that everyone has argued about for ages, or since people realized position was important in holdem.

Since you are new to limit holdem, I would actually suggest you fold AJo and KQo UTG until you feel confident about your game. Once you are convinced you are a winning player, you should be playing AJo and KQo no matter what your position. Whether to raise or call with these hands UTG in a 10 handed game really doesnt matter IMO as long as you dont fold.

However, given that you are just starting out at limit holdem, I think you would be better off playing tigher than normal and folding AJo and KQo UTG until you know you are a winning player. This will lower your variance, and you are giving up almost nothing in EV, in fact you might actually be making money/saving money by folding in this spot, since playing AJo and KQo UTG may not be +EV for you.