Here are 2 important videos to help direct one in the right direction.
Controlling ones thought can be tricky if it's even possible at all. Overcoming our self deception is the game, approaches can become crutches in the case of ones impulse to seek external solutions to the point of diminishing return.
How what we resist persists.
The concept of inversion is useful in the case of intrusive expectation.
The "Backwards Law" is here to change the way you see thought control.
The first step in finding oneself on the fortunate end of any given heuristic, is to recognize it. Then simply aim to attach a concept or notion to your existing knowledge tree, and harness its application in any way possible.
"What is easy to do is also easy not to do" - Jim Rohn