Hand 1: I think you should just fold pre-flop with such a modest hand, if it was suited it's an easy raise. I just don't like raising such weak hands unless the table has been very tight. Anyways, the river call is iffy. You obviously only beat a bluff, so it comes down to how much you really think he's bluffing.

Hand 2: Interesting hand, I like the way you played it on every street. The river card is terrible, completing both flush and straight draws, so I check behind here and hope I'm good.

Hand 3: I think you played it well, except I think a better play is to just call the turn and lead out for a small bet on the river. A lot of times this induces a raise from your opponent on the river, the c/r is fine though.

Hand 4: I don't like the way this hand played out, I would fold pre-flop to his reraise out of position unless he had been doing it a lot. On the flop you should put in a raise. If he has nothing he'll probably fold, and either way you'll be a lot clearer on where you stand in the hand. If he has an overpair he'll almost certainly elect to reraise you, and if he missed with something like AK or AQ he'll probably throw his hand away.