How to control where I bowl the ball?

A simple way of training control of line and length is to put a marker the size of a piece of paper (A4) on a good length. I regard a good length for a fast bowler as being four walking strides from the crease, down the wicket, put your marker down on the line of off stump. You can use a plastic coke bottle with some water or sand in it or a piece of old carpet as a marker.
This drill can be done in season or for pre-season : You will also need a notebook to mark yourself on success rate for overs bowled.

Six balls times six overs.

Make sure you have fully warmed up with a run around and stretch.

You are going to bowl 2 overs off your normal run up to warm up.

Then I want you to bowl 6 overs twice a week, with a days rest in between.

The first 3 overs will be off a half run where you will keep your eyes focused on your target. Bowl the ball with full intent each delivery

Mark every time you hit your target.

You are then going to bowl 3 overs off your long run, again with full intent to bowl quick.

Again monitor your accuracy, as you practice this your control will improve as each week goes by, aim to improve from week to week.

You can use this for each delivery you want to work with, yorkers, slower balls etc.