So here's a few tips which I find useful when playing. They're from an amateur, me, and I'm sure many of the pros would not endorse them. But I feel I've done well playing Texas Hold 'em the Marty way. And I feel confident that some of the pros would endorse some of my methods anyway.
It's almost always bad to go all in on the first two cards. You should only do it with a pair of Aces, or with Jacks or better when you hold the fewest chips at the table. The game changes too much over five shared cards, and by my experience you lose better than half the time even starting with that pair of Aces. Generally speaking, don't go all in on two.
You will lose more hands than you win. That's the nature of the game. So while it's okay to be aggressive, and you do have to be a bit of a bully to play well, the cards will be against you more often than for you. Be selective with your aggressive play, and remember there's a fine line between aggressive and foolish.
If after the turn you need two cards to earn a decent hand, play conservative and be ready to fold quickly. The numbers are against you; you aren't likely to get both cards.
Bet from strength. If you have a hand which looks very difficult to beat, be aggressive. An easy example I think is when you have any two hearts and three more are on the board AND a straight flush is unlikely. Push that hand hard.
I do not like the bluff. It's too dangerous. Still, you should place small bets or make small calls often enough even with lesser hands to keep your opponents unsure of your tactics. Part of the game is creating uncertainty about your motives. That, however, does not mean betting to 'make things interesting' as a very poor player I know will often do. The game is interesting enough as is.
Beware the wild bettor. He's usually very aggressive or very stupid, and probably the latter. Don't get into raise wars with them. They're depending on luck and, I mention again, the cards are generally against you. They will win at times despite their stupidity. Let the others at the table deal with those players. They'll usually burn themselves out within a few hands; why lose your chips trying to make that happen?
Don't call a high raise unless you know you've got the cards to beat it. I know, you can never really 'know'. But a clear headed study of your hole cards against the common ones will usually give you all the information you need.
I think that's all for now, although I believe I'll share more tips later. But I can't give away too much, of course. I may play you one day.