I will start this article by explaining the term value bet to novice poker players. Value bets are fairly self-explanatory. It's a bet you make at a time where you think you have the best hand and you want the other player to call your bet. Generally these bets are made on the river, but it can also be on the turn. The really good players have the ability to make thin value bets as well, meaning they extra value from marginal hands when its not so obvious whether you should bet or check.

The most important factors to take into account are the image of your opponent(s), the pot size and of course the strength of your hand. For example, when your opponent is very loose, it might be a good play to bet for value with a mediocre hand like say middle pair. The reason for this is because they will call with a lot worse, sometimes ace or king high.

If your opponent is a very tight player, it might be better to hold back a little because he probably won't call unless he's holding top pair or better. Against these kinds of players, you usually want to pot control with marginal hands, because our opponent is only looking to build a big pot with a strong hand.

If your opponent is rather aggressive then you might want to hold back a little too. For example, when you are holding top pair and a good kicker, and you are fairly certain you have the best hand, but you opponent tends to re-raise on the river with both strong and medium hands, you might want to check back to him on the river in order to avoid getting re-raised (all in). Chances are he's holding nothing, but he might have been slow playing a monster and in general you want to put your opponent to the tough decisions and you must try to avoid having to make them yourself, so checking might be the best option.

The opposite might be happening too, you're playing a passive player. Passive players tend to call rather than raise. Against these players value betting is very often the best move. They will generally call you off or fold, so if you raise in situations where you're most often ahead, then in the long run, you'll make good money value betting. The player type you should value bet against the most is the loose-passive player who will, on average hold on to the worse hands and will call you off with those hands.

Why you should be less likely to value bet loose aggressive players.

Loose aggressive players tend to get tricky and they can put you in awkward spots with marginal hands. Unless you're betting to induce a bluff, you probably want to pot control in these spots against these kinds of players. They enjoy mixing up their game by being aggressive with draws and they tend not to call their weaker hands down to the river. They rather fold or bluff with those hands and maybe call you down with a monster and re-raise you in which case you have to make a tough decision for a lot of chips, and you get in a situation you really want to avoid.