Hand #1
Big Slick AND TPTK is often a dicey hand. If your villain is very loose or overvalues hands, then cold calling like you did was probably fine and if you have a read that your hand is good, a re-raise on the river wouldn't be a bad idea either. Against a tight, competent villain, you really have to be careful when HE leads out against you on the flop. When you have the lead pre-flop in a hand and someone leads INTO you on the flop, that's a red flag. With no reads, I think a re-raise is the best play so you get an idea where you stand. If he calls the flop re-raise and leads out again on the turn, you have to assume you're beat. So, the way THIS hand played out with no reads, I'd assume you're beat. I always assume a player is tight, ABC until they prove themselves otherwise.

Hand #2
I don't like calling raises with a weak ace let alone 3betting them. The fact that it's suited doesn't overcome that it's a weak ace. You have a 1% chance of flopping the flush and when you get your draw, you have to hope or have a read that you'll get about 20% odds to see one card or 36% to see two. The bet on the flop isn't bad per se because you keep the lead, have fold equity, and have outs to the nut flush. Without a read, you obviously have to fold to the all-in. This is good example of why we need a good pre-flop strategy as without one we can quickly lose money because the hand gets out of control.

Hand #3
I don't like the turn bet with the flush. You have to ask yourself, why would villain stick around after my c-bet and more importantly, why would he now go away on my turn bet? With this board texture, a heart flush draw is the most likely reason and now you're building the pot for him. With just an over pair, I don't think you want to build a big pot even if you may have the best hand. This is a situation that comes up a lot where a player generally doesn't want a big pot but doesn't want to fold either, so they try to compromise and call and hope he stops betting or you hit trips. Trust me. I can relate and I've been guilty of this, too. However, I think a better play is to get a read on your villain and either fold to his flop bet OR raise for value or for information on the flop. If he calls the flop re-raise, you know for sure where you stand and really have to shut down - ESPECIALLY if a draw gets completed. This method allows you to find out better where you stand EARLIER for much cheaper than it would to still be confused for more money on the turn and river.