[Dice Man]

I was bored today so I started playing games at tables that I know I'm crap at. I tried Omaha, 5 Card Draw and 7 Card Stud, and made money on all of them. I doubled up twice in a row on Omaha without really knowing what I was doing.
ANyway I played a bit more of this 5 Card Draw A-7, and I still don't understand it, but it seems easily beatable. It seems to me that a simple system will make money with it. How many cards are there in the deck, because I keep being dealt trips and two pairs and stuff? It sems like it's rigged somehow but I'm not quite sure how.
Also I've noticed that every now and again if you raise pre-draw and then stand pat and bet again you get a lot of folds where usually people mostly call. I assume it's because they think you started with a straight or better. I've used this to bluff a few down, and it seems really silly to just plan before the hand that I'm going to make this move regardless of what my hand is, and it working a lot of the time as well.
So anyway these are my hunches about how to play hands, but I'm not sure if they're right if someone could advise me whether they're decent plays.

I only (willingly, ie not blinds) play hands where I start with at least a pair, though it has to be a royal pair because I suspect people start with a pair about 80% of the time. If I have a pair I discard the three other cards even if one's an ace.
If I start off with 4 of one suit I play and discard the unsuited one even if it's a pair.
If I start with trips, 2 pair or better I raise pre-flop. If I had 2 pair with aces I won't discard the other card and will just stand pat. This is so I can attempt the "straight" or better bluff and if someone calls with 2 pair I'll usually have them beat anyway. If they had trips they'd probably be tempted to call even if I represented straight or better anyway.
If I start off with a hand like TJKA9 I shouldn't play it should I? Instinctively I think the chance of hitting a gutshot is low, and a single pair won't be enough to call a raise with. But after playing this game a bit I get the impression there's some weird mechanics going on whereby they're just throwing your outs at you so that you bet more. (I'm not suggesting any kind of conspiracy but it does seem a bit like that). About half the time I've had a single pair pre-flop and thrown away 3 cards I've ended up with a full house. Nearly every time I started with pocket jacks so I don;t know why the hell this is happening.
And if I do start off with a hand like TJKA9 and I get a free draw, should I go for the gutshot? I get the feeling it's better odds to just throw away everything and hope for some amazing hand. Especially as if the others see you throw away every card they think they can bluff you out of it. Or should I keep the ace here and throw the rest?

At the moment I'm getting stupidly addicted to this game. It seems to be like playing a fruit machine or something. Once I know more about it I think the addiction will end and I'll either avoid it or start milking it.

Oh yeah, Im playing this on 25/50c. I can't believe some people are playing it on $20/40. That suggests that there might be some skill in it.