The first thing to consider is balance. Balance is important in any sport and snooker is certainly no exception. Good balance is obtained by having a good stance. To find your balance is the first thing you must do if you want to play snooker. If you are solid on the shot then you will be able to pot with more consistency.
The next time snooker is on the TV, watch where the players position their feet. See how the front leg is bent and the back leg is kept straight. This gives a strong base from which to gain that all important balance. The position of the feet is also vital. If your feet are out of line then your whole body will be.
For this first part, try to concentrate on the way you stand. Stay down on the shot after you hit the cue ball, until the object ball is sunk. Make a mental note each time you go down on a shot and each time you stand up, of key positions of feet and legs. If you follow this as a rough guide then, assuming you are right handed, your left foot should be pointing in the direction of the object ball, but angled slightly outwards, and your right foot should be angled roughly toward the black spot.
When you are playing for position, make up your mind how you are going to get on the next ball and position the tip of the cue accordingly. The last thing you should be thinking about before you strike the cue ball is the pot. In fact, all of your efforts should be on making the ball go down, because if your technique is good then your tip should have struck the cue ball where you decided and the cue ball should go roughly where you wanted.
If this is not the case then you have not struck the cue ball where you intended. This means you probably moved on the shot or your stance was wrong, or both. In any case, if the object ball is sunk and you are out of position, you can at least play safe! A good safety shot is sometimes better than a pot.