I am someone who thinks about something or the other all the time, read worry sometimes too!! So in order to help myself, I had decided that I would not think too much about anything and just go with the flow!! It is indeed, really very difficult for me, but something that I am trying to cultivate for my own self!
A friend once told me that you should learn to detach yourself from self...no this is not the way to attain nirvana or anything, it is simply a technique to view the events or things that happen to you, as a viewer...detached from yourself. It is called 'kamala sanyaas'....similar to the 'Lotus' flower. If you notice a lotus closely, the water does not stick to the leaves....it remains detached from the leaf/flower, hence the comparison! So I try and keep telling myself not to think negatively or worry about something that I don't have control over...but I am so wierd...
..Like S once told me a story about a guy who would complain of headaches and go to a doctor regularly with the same complaint. The doctor figured that there was nothing wrong with him to cause any headache and realized its all in his mind...so he said everytime you suffer from a headache, take these pills...but try not to think about monkeys when you take them!!
Invariably, the guy would only think of monkeys everytime he needed to take the pill... :D
Similarly, I start thinking about why I don't worry about the things I used to...now...ya! Go Figure!!! :-)