Big hands/Bluffing
Preflop > Pairs > Draws > Big hands/Bluffing > Other
You might be wondering why I'm grouping big hands and bluffs into the same category, seeing as they're pretty much the exact opposites of each other. The reason for this is based on the simple fact that when you have a big hand you want your opponents to think you're bluffing, and when you're bluffing you want your opponents to think you have a big hand. If you're playing against really bad players you might be able to do this by just slow-playing big hands and betting when you have nothing, but against decent players the best way to do it is to play your big hands and bluffs similarly. This means that if you often bet out on the flop even if you have nothing you should seriously consider betting your big hand hard, and if you play very passively with nothing you definitely shouldn't bet right away when you hit it.
Of course, there are other considerations when playing a big hand. The main one being the possible draws that can beat you and their chance of hitting. Let's say you have 77 in 3rd position. You flat call, and so does the person in 7th position. The person on the button makes a small raise, 3x the big blind, and the table folds around to you. Since it's so cheap for you to call, you do, and so does the person in 7th position.
Now the flop comes 7hThQs; you've got trips. Obviously there are some major possible draws out there- there's two hearts so there could very well be a flush draw for someone, and the ten and queen could be making somebody a straight draw if they have say KJ. Because of these draws you should bet here regardless of whether you've been playing passively or aggressively. The only question is- how much? The short answer is- a lot. The simplest reason is to make it impossible for a drawing hand to flat call; you have to force their hand and make them decide whether they want to push you off your hand (which would be wonderful since you can then re-raise them all in) or fold (which is also fine for you). Another reason, possibly even more important, is that by betting big (a pot sized bet, or maybe even slightly more than that) you're pretty much representing a drawing hand, i.e a semi-bluff. Since there was a raise preflop, and there's high cards on the board, it's very probable that someone has top pair with a good kicker or even an overpair. They're very unlikely to lay that down to an "obvious" overbet and may even raise you to try to get you to fold your "draw" ;)
Now to the subject of bluffing. A lot of people don't feel very comfortable bluffing and for good reason i suppose, you're bound to get caught in a compromising situation once in a while. The thing is, getting caught is part of the positive of bluffing and not just a negative. As i said earlier, if you've been playing aggressively and bluffing you can bet your big hands more aggressively as well. That means more money in the pot and more callers. If you've been playing tight all game, you can slowplay and induce a bet, but once you raise you'll have given away the strength of your hand.
If it still bothers you to bluff, just think about it this way- since you have nothing, you'll be able to fold to any kind of raise without remorse. Whatever money you're betting, that's all that you're risking. Really, bluffing is the least stressful and least risky play in poker (other than holding the nuts). I'm not saying you should go crazy, you should always be thinking about what hand you're representing while you're bluffing and what hand the other person would fold in this situation, but throw one in once in a while. And if you get caught- use it to your advantage later.
