Golfers who have a problem hitting the ball too low usually take too short a backswing or have too much lag in their swing which takes loft off of the club at impact and drives the ball lower than desired
The best way to read greens is through experience, I like to take eight balls and roll them to a hole at different speeds and on different lines, then with the eighth ball I putt it by picking the best speed and line to get the ball in the hole
Develop control and feel for pitching distance by creating a set position on the backswing as your benchmark and then vary your shot distance by the power you swing with