Conventional Wisdom says that when you're first to enter a pot in NL cash games, you should open with a raise. Raising puts maximum pressure on the other players (and the blinds), and will help significantly in defining the opp's range if they call your raise. I try hard to follow this advice of opening with a raise, but it begs the question of how large these opening bets should be.
Another school of thought is you should mix up your raise sizes on a random basis. Varying your bet size between 2.25x and 3.5x the big blind is not a bad option, but keeping your bets truly random is tough, particularly after you've been playing a while, and especially if you're multi-tabling. Some people use the second hand of a clock to randomize their bet size, but it takes discipline to use this technique.
I've also read the strategy of never varying your bet size. Always bet the same amount, and your opponents will not be able to deduce anything from your raise. IMHO, this is actually pretty good advice, and until recently I have been an adherent to this technique. It's very easy to simply hit the "Pot" button when multi-tabling NL to ensure the opening bets are all the same size. This works out to a little more than 3x the big blind if you're first in, which is a pretty good average-sized bet to make.
Okay, all that said, I've been reading some posts on the forums lately that suggest a slight variation on the constant bet size approach. I believe this strategy was first postulated by Chris Ferguson, so I will call it the What Would Jesus Bet (WWJB) method hereinafter.
Ferguson says that raising from early position advertises that you have a very strong hand; i.e., one that can beat all players who still have to act. Since you are representing such strength, it doesn't take as large of a traditional raise to convince the other players and the the blinds to fold. Even better, since your hand is presumably so strong, you actually don't mind a call from another player, especially the big blind, anyway. The other reason for a smaller sized raise is that you have so many players acting after you, any of whom might wake up with a monster and re-raise you. If you have AQ, for instance and raise in EP, but then get re-popped big, you can let the hand go and it cost you the minimum amount.
In contrast, when you raise in late position, you are essentially saying that your hand is strong enough to beat only the two or three remaining hands yet to act after you. This allows you to raise with more marginal hands, but smart opponents know this about your range, too, so your raise must be bigger than "normal" to make them think twice about calling or, worse, re-raising.
Ferguson goes on to recommend that in EP, you should raise 2x the big blind. In MP, you should raise 2.5x the big blind, and in LP you should raise approximately 3x the big blind. I've tried these values, but at the $10 tables, they don't work quite as well as they do at the limits Jesus plays at. For my small stakes games, I've found that a 2.5-3x bet in EP and MP is about right, and a 3.5x bet in LP generally works. I vary the actual amounts a little based on how tight the table is; at a tight table, I err on the small bet size, while at a loose table I tend to increase my bet size a little.
Anyway, this is a slight variation on betting that I'm trying to incorporate into my game. It's a little hard to not just hit the Pot button, but I'm working on breaking the old habit and incorporating the new one. I'll report back later how this is working out...
All-in for now...