Math is not the only aspect of poker you have to care about. There are a lot of psychological aspects you have to deal with, too. There are 3 key mind games you could use at a poker table: Slowplaying, Bluffing and Semi-bluffing.

Bluffing

In low limit games ($2-4 or lower) bluffing is almost useless since the game limit is really low a lot of players tend to call for a showdown. It is a very difficult task to scare your opponents to get to the pot, so bluffing is better left for high limit or in no-limit poker. In case you want to bluff, remember that you have to "represent" something to achieve the bluff, for example: if you bluff with just a high card on the flop, you are "representing" a pair, or if there are 3 suited cards in the flop you are "representing" a flush in your bluff.

Semi-Bluffing

This is when you have the possibility of getting something in the next card. You have good cards but not a strong game yet but you have a chance of a hot hand in the next rounds. This works better if you are playing no-limit poker. For example: if you have an Ace and a King Suited, and in the flop only get dealt 2 cards of the same suit, you decide to raise without a pair, just a high card, because you have the possibility of ether getting another card of the same suit dealt for a Flush or another king or Ace for a high pair.

Semi-bluffing

This is when you have the possibility of getting something in the next card. You have good cards but not a strong game yet but you have a chance of a hot hand in the next rounds. This works better if you are playing no-limit poker. For example: if you have an Ace and a King Suited, and in the flop only get dealt 2 cards of the same suit, you decide to raise without a pair, just a high card, because you have the possibility of ether getting another card of the same suit dealt for a Flush or another king or Ace for a high pair.

Slowplaying

You are trying to deceive the other players into thinking you have a lower hand than you have. For example: if in the flop you get dealt a full house there is no need to scare away most of the players since there is little chance for any of them to hit a better hand. You just wait for the Turn or the River to raise and watch the pot get larger. Remember to do this only when you ether have a strong hand with a little chance of your opponents to win over you, or you can improve your hand with cards likely to get dealt and that will not represent any benefit to your opponents.