The biggest mistake for beginner poker players is playing too many hands and playing too passively. It is important to wait for decent hands and throw away the junk hands. The big pairs such as AA, KK, and QQ are by far the most profitable starting hands in poker. It’s very important to play them in a manner that maximizes your profit because these hands have very high positive expectations and are quite rare. Just like other situations in poker where you have the best hand, you want to build up the pot quickly without allowing opponents to improve their hands by getting to see the flop, river, and turn for cheap.
In most situations, when you have a big hand you want to build up the pot by taking the lead with betting and raising. However, there are some situations where you may want your opponent to be the aggressor and do the betting for you. You do this when your opponent is incredibly aggressive and they bet and raise frequently with poor hands. You should play it a bit different if you have a large stack. This is because if you go all-in on the river with a big stack, you will almost always be beaten by a two pair hand or better. As the stack and pots get bigger, the better the hand you need to see a showdown. Often even strong hands like two pairs and sets are no good when a lot of money goes in the pot on later turns. So if someone re-raises you on the turn or river with scary community cards, you may want to think about folding your high pair.
When you play a hand in poker it is important to plan the hand in advance. Why are you playing that hand and how are you going to play it? Too many players just play the hand because they like the look of it. They have succumbd to the “calling reflex” which is the idea that people have a tendency to want to call, even often without thinking about it beforehand. People don’t come down to the local casino or play online to just sit there and fold all day. People want to play hands. Small pairs and suited connected cards can be very profitable in no-limit hold ‘em. Hitting sets and making flushes and straights have the potential to win big pots. They are often quite deceptive, especially straights like double guy shots, which are very hard to see, often surprise opponents, and even put them on tilt.