Probably billiards are played by almost everywhere in every country that most of us may miss or not know some basic etiquette of playing billiards. Actually most os them are just basic down right common sense and courtesy, please respect the billiards sport, don't get yourself rowdy over a miscue and tarnish it's image.
The very basic and important rule is do not make yourself a distraction to the player. Making sudden loud noise and fast movements may distract the player. But most of all, never stand or cross in the line of sight of the player. What is the line of sight? It is purely the path of the eye of the player focusing along his billiard cue tip ball. If you are unintentionally in the line of sight of the player, simply stop moving of cause acute movements of the body until the player completes his shot, just be courteous. This too applies to your neighbouring billiards table who is playing, be polite, who knows, you may make more friends this way and probably gain more knowledge in billiards.
Also be cautious when you move around the billiard table, your opposite player may suddenly jerk up his billiard cue from behind and hit you and get hurt. He may even spread his legs to get a more stable stance, this way you can get yourself being tripped over by his legs.
When you are in a situation where you and the opposite player occupying the same spot or position for the next shot, be polite and allow him to play first. It is always better to have the other billiard player go for the shot first, there is a reason to it. When the first billiard player is engaging the shot, believe you me, he is not completely focused on the shot