We hear of so many mind control techniques. There are so many forms of meditation that are available.
Having experimented with many such forms of meditation and mind control methods, I find that the best one is to simply observe your breath!
We have voluntary control over our external body parts, but no voluntary control over what goes on inside our body like beating of the heart, churning of food inside our stomach etc.
However breathing is the only aspect of our living mechanism, which goes on involuntarily as well as we can have a voluntary control on it (to some extent).
Breathing connects our external body with internal system. Hence you can say that breath is the vital life force without which we cannot stay alive.
Breathing also is a good tool for meditation and exercising control over our mind. Say for example if the mind is disturbed, your breathing becomes heavy. When we are peaceful breathing happens in a relaxed way.
Thus breathing can be used as a tool to control the thought process and bring our mind in control. One has to simply practice observing one's breath.
With practice, you can start controlling your mind by monitoring and regulating your breathing.