Each pool game is different, 9, 10 ball demand shot accuracy at all speed and with all english of which in my opinion once mastered, one can move to other games. The 1st objective of any shot is to pocket the ball (unless you are playing safe); so some shots do require english to pocket others do not. Some safe requires english to throw OB such that CB remains hidden, After a while a good player, or a pro develops a habit for certain shots to afford them best chance to pocket the ball without jeopardizing position. Take for example
CJ, is making a DVD and the title (TOI) that is tip of inside which suggests that every shot should be shot with some form of inside english; TOI requires you to shoot with speed, cannot baby them..so you have to get the feel for that which is another form of shooting, i call it personal form.
I do like Oyster's instructional YouTube stuff, check them out:
http://www.youtube.com/watch?v=Ju3Vjjz-D5Q&list=UUOVP4Wmcp20VIQkB0ssPWnw&index=8