Summarize:

Grab the cue near the bottom of the thick, weighted end. The closer to the end you grip, the more control and extension your shots will have. Make sure your hand placement is comfortable and secure to prevent the cue from drifting when you’re aiming.   Snooker cues tend to be somewhat heavier and have narrower tips than the cues used in other forms of billiards. With a slender tip, the player can manipulate the cue ball more precisely. How high or low you choose to place your hand on the cue is mostly a matter of personal preference. Lay your non-shooting on the table and use it to guide the cue as you shoot. Most people prefer to use either an “open bridge” (lining up the cue across the groove of the thumb joint) or a “closed bridge” (enclosing the end of the cue between their thumb and pointer finger). Bridging helps you steady the cue as you strike the cue ball, allowing you to place your shots with more precision.   Use a solid bridge to keep your cue from wiggling around during your stroke.  Elevating your bridge by lifting the bottom of your hand off the table can enable you to pocket balls that are too close to the rails or other balls. In one tight, controlled motion, draw your shooting arm back a few inches and thrust it forward, hitting the cue ball in the upper part of its center. Keep your elbow relaxed and close to your side. Try to make your movements as fluid as possible. A jerky or halted stroke will most likely be inaccurate. Practice shooting straighter by bouncing the cue ball off one of the rails and seeing how closely it returns to the tip of your cue. Sink balls by shooting them straight for the pockets, or striking one side of the ball so that it rolls in at an angle. You can also use the rails, or the edges of the tables, to bounce balls into pockets on the same side of the table you're shooting from. The balls will be in many different positions throughout the game. Take some time to line up your shots every time it's your turn at the table.  Keep your eye on the ball as you line up your shot, and don’t let your shoulders come up until you’ve completed your stroke. Calculate the angle you need to strike the ball in order to knock it into a given pocket by aiming for the point on the ball that's directly opposite the pocket's opening. Because of the size of a snooker table, and the number of balls cluttering the table, there may be times when it’s impossible to make a successful shot using the standard technique. In the situations, an extension tool such as a "rest" (also known as a “bridge”—not to be confused with the hand position used while aiming) or "spider" will come in handy. Rests resemble normal pool cues with the exception of an arched stand at the end. The player’s cue can be fitted into this stand, which takes the place of the bridging hand for steadying shots.  A rest is a valuable aid for making shots that would otherwise require you to lean across the table. The spider extension has a higher arch, and should be used in situations where the cue ball is too close to a ball or group of balls to give you a clear shot.
Take a comfortable grip. “Bridge” the cue with your non-dominant hand. Move the cue in a smooth, straight line to shoot. Use a precise stroke to place the balls into pockets. Use extensions to assist with difficult shots.