Who can stop himslef from thing..

umm... an interesting question , ok ill try to do this . actually its a bit possible , but only through concentration . though seemingly difficult but if u practice then i think it is a quite possible. u too try concentrating and then give ur feed backs ,pm me when u get a result for this problem.

As a child working on the farm I used to try to stop thinking and found that I was thinking about trying to stop thinking. Instead of being bothered by this, I found that putting good thoughts into my mind and working on positive thoughts is the way to go. It is work but I would rather practice thinking good positive things and then it's not so bad to be thinking all the time.

You can't, really. As humans, we tend to OVERthink pretty much EVERYTHING - it's annoying! Maybe try busying yourself so you have LESS time to think. That seems to work for me, sort of.