Before the Flop
Go all-in from any position if you're holding AA, KK, QQ or AK, even if someone has raised before you.
If you're sitting in middle or late position you should also go all-in with JJ or AQ, as long as no one has raised before you.
If you're holding smaller pairs from two sixes upwards in middle or late position you should raise from four (or more) big blinds, as long as there hasn't been a raise up till then.
In late position you can afford to see the flop even if you have speculative cards, as long as there hasn't been a raise. That means you are limping (only calling the big blind) with: two fives, fours, threes, twos, a suited ace and the so-called middle to high suited connectors. These are two sequential cards of the same suit, such as a seven and six or a queen and jack.
After the Flop
The central question after the flop is: Do you have anything? If not, then the round is over for you.
If you have two pairs or better, then you go all-in.
If you're holding a flush draw or open-ended straight draw (OESD), you should only go all-in if a number of opponents have already continued to put chips in the pot.
If you're holding a top pair, i.e. a pair made up of one of your starting cards and the highest community card, then you only go all-in if you have a maximum of two opponents. Proceed very carefully if you're playing against more than two opponents.
How do you play the late stage?
The late stage begins when you only have about 20-25 big blinds left in chips. The strategy you have to follow in this case is: raise or fold. So you either raise or fold preflop. And as soon as an opponent after or before you raises you should go all-in or fold, depending on the cards you have, of course. Just pressing the call button with the intention of looking at a flop or limping is strictly prohibited from now on.
Take a close look at the players with low chip stacks. You'll need decent cards to play against them, because they're just waiting for the opportunity to throw all their chips in.
Be sure not to challenge aggressive players who have more chips than you do. You'll need to have a strong hand to play them.
Before the Flop
Raise in any position if you're holding AA, KK, QQ, JJ, TT or AK to about four big blinds. If anyone raises that, go all-in.
Also raise in middle or late position if you're holding a pair of nines. This also goes for KQ, AJ and AQ. If someone raises after you, you should go all-in if you're holding any of these hands, except the KQ and AJ - if you hold those two hands you should fold to the raise.
After the Flop
At this stage the round is decided on the flop at the latest. This is simply because the pot is so big, that you won't be able to back out once you've decided to continue playing.
If you've raised preflop and only have one opponent, then bet about half or two-thirds of the pot with any hand. If you are raised, then go all-in with any top pair or better, or a flush draw. This also goes for when you haven't hit anything, but your two starting cards are higher than any community card (overcards)...all.time..this..???