winning poker strategy

Here's the biggest mistake most people make, calling too much. There simply aren't many flops that we will like with any hand. The large majority of the time you will miss the flop with any hand. Even AK misses the flop most of the time.
The player who takes the lead preflop will win the hand the large majority of the time over the long run.

Calling a preflop raise too light is a serious leak that most online poker players suffer from. So don't be ashamed to admit that you are calling raises you shouldn't be - we all do.
As far as costly mistakes go, it's far less costly to fold too much than to call too much. So tighten up your calling requirements a bit, and know that you are saving yourself money.
This article will look into one of the most common leaks that poker player suffers from, and will help you to make profitable adjustments to your preflop game.

Calling a Preflop Raise

So should you never call preflop? No, not at all. But there are certainly hands that you should do it with, and others that you shouldn't. With poker pairs Nine or lower and suited connectors QJ or lower you want to get in the pot cheap with a high likelihood that somebody will pay you off if you hit. So calling a preflop raise with these hands preflop is often the right play.
These are hands that have the opportunity to flop monsters. When they don't flop monsters they are easy to get away from. These hands also play very well multi-way. Having three or four players seeing the flop makes it more likely that you will get action once you flop your flush, straight, or set.

The Trouble Hands
The hands that cost people money are AT and lower, and King Jack and lower. There are also players who call preflop raisers with trash like Q10 offsuit, or worse yet random hands like 10 7. It is safe to say that these hands are also unprofitable to call preflop raises with. All of the hands above are -EV to call a preflop raise. Sometimes AT is playable to a preflop raise, and occasionally KJ, but not all the time.

It's important to realize that most of the time it's a play that will lose you money over the long run, and to know the factors that would make calling with these hands a good play.
In the case of KJ, you should never call a preflop raise out of position, and you should only call in position if you can come up with a good reason why you're doing it.

In the case of AT, this is one of those spots where you need to be careful. For most players, calling with AT preflop out of position will be -EV over the long run. Many players lose money overall with AT, and eliminating out of position calls, and situations where you are calling a preflop raise made by tight players, would bring most players out of the negative. However, if your opponent has a wide range of hands they would raise with (hopefully including A2-A9 and KJ) then you are likely crushing their range. If your AT is suited, you're in position, and your opponent has a wide range of hands they would raise with, then a call is always the right play. Needless to say, all junky Aces like A8, A3, etc, are -EV to call preflop raises. Most of the time you won't flop an Ace, and you will lose money when your opponent has a better Ace. It's very -EV to call a preflop raise with a junky Ace.

The biggest problem occurs when you do flop an Ace on a draw heavy board. Now you need to protect your hand, but your hand is so weak that you can`t play it very hard without finding yourself in a tough spot on the turn and river. Does your opponent have a drawing hand or a higher Ace? It's very hard to figure out the answer to that question before the showdown.
NOTE: Please keep in mind that I'm referring to full ring games, and to a lesser extent 6-max. Obviously, AT is a monster at a heads-up table, and at a six max table it is also a fairly strong hand. Also, I am referring to calling a raise. AT is a great hand to raise, and it would usually be a mistake not to raise it. However, once there has been a raise you have to look at things differently.

What About Re-Raising?
Everything above in relation to calling a preflop raiser applies to reraising. The difference with reraising is that you have the chance to take the lead, and you also have fold equity. Therefore, it is often favourable to raise instead of just calling.
For example, if I flop middle pair top kicker I will often check-raise to find out where I stand in the hand. I don't want to be calling bets on all three streets to find out, "Oh, he did have top pair, woops". I want to put out one single bet to try to take down the pot.
Another example would be AK preflop. If a player in middle position raises, and you have AK on the button, you will usually want to take the lead by putting in a reraise. That way, even when you miss, your opponent is likely to fear overpairs and check to you. You can then put in a continuation bet and take down the pot most of the time. If they do play back at you, you are beat.

Summary

Most players understand reraising requirements far better than calling requirements. Calling is only for hands that are likely to be clear favorites on a good flop.
If you call with hands like KJ or AT out of position too much you will find that you are losing big pots because your opponents often have a higher kicker.
Leave those mistakes to your opponents. Either take the lead in the hand and play it aggressively, or throw your hand away and wait for a better spot.
But above all, stop calling out of position with KJ or worse, it's such a huge leak.