The problem with the first hand is that your bet got no one out of the hand. You are in early position, although that's not to say you should/shouldn't be raising here. But if you're going to raise with AT OOP, make sure it's enough to get a few people out of the hand or take down the pot pre-flop. C-betting here would have been a good move if you didn't have 4 players left to act behind you. But - you took a stab at it and knew when to fold.

I usually limp behind/check my option when in the blinds with AT/AT suited following a bunch of limpers. This way, I don't feel obligated to c-bet, hence checking whether I whiffed or hit the nuts.