General thoughts:

Raise pre-flop a little more (hands 2 & 4). Definitely to $1 probably $1.25. Bet flops at least 1/2 pot, preferably 3/4 (hand 2). If there are lots of players, bet full pot. Don't play unsuited aces lower than AQ, unless open-raising from LP (hand 3). Don't always slowplay your sets on the flop (hands 1 & 4). You want to build a pot and the longer you wait, the harder it is. Not to mention you make them pay for their draws (hand 4).