1. Good general advice for AK is: play it aggressively preflop and give up postflop if you miss. Boards with two lower broadway cards usually give AK very good equity and a good semibluffing opportunity, especially to get villain off an underpair. On low card flops it's better to just muck.

Your weak looking cbet is totally pointless here. Just check behind and hope you hit the turn.

2. You played it fine. You can also raise preflop. The flop call is good. I would also have bet the river, but as played call expecting to be behind most of the time.

3. Learn to always cbet same amount, 3/4 pot is good. Later you will learn to vary cbet size according to board texture etc, but it's not needed at microstakes.

4. Don't post this kind of really boring hands.