Simple questions but no really easy answers.
Videos of good players is helpful. Watch what they do with the cue ball when playing defense. Getting safe is an extremely important part of the game, especially early on after the break. You also have to get out of your opponents break with a pretty good degree of success. Videos will show you how to do this. It will then come down to execution, which takes practice. It's one of the few games you can actually learn something by watching a video.
It is nothing like rotation games. Just because you see a shot you think you can make doesn't mean you shoot it. If you make the ball are you going to have another shot? Are you going to stick yourself behind another ball or the rack so you cannot see the balls by your opponents pocket if some are there? If you miss are you putting the cue ball where you opponent has no shot, or a very difficult one at best? Many time a shot cannot win you the game, but is sure as hell can lose it for you. You don't want to overthink it, but you do have to weigh your options and percentages. Playing more and getting some experience will help in these decisions.
Some of the best moves involve just bumping a ball or a few balls out of the rack towards your pocket and sticking your opponent behind the stack or another ball. Cue ball movement and control are very important.
If you don't have anything by your pocket, try to get something over there while not making it easy for your opponent to just knock it away. Sometimes just getting it on your side of the table, not even close to the pocket will do. With no threat on your side of the table you opponent is just going to fee wheel on you and try to make any and every shot as he knows if he misses, there is no penalty for him to pay.
Keep the cue ball glued to the rail at every chance. I don't care how good a player is, they do not like shooting off the rail. It severely limits what they can do with the cue ball and makes shots harder. Distance and the rail are your friend, unless of course his ball is just hanging in the pocket. Learning the right speed to keep your opponent on the rail comes with practice.
You have to be able to make balls to win, but this game is not just about making balls. You have to get out of the rotation mode and get into the one hole mode.
I would practice short rail banks, long rail banks, caroms, combinations, and as stated above, break the balls and see how many you can run in the same pocket with ball in hand. This will teach you how to get position in with lots of balls crowded around the end of the table. Also watch videos. Many times the solution to the problem is very simple and doesn't take Houdini to get out of it.
That's probably more than you asked for, but it will get you started.