What are some good meditation techniques to practice to clear my mind?

I believe in the new age concept of the law of attraction. To get this to work I need to learn to master my thoughts. I tend to have a little anxiety. I want to eliminate the anxiety I have by filling my mind with positive affirmations. From what I have found out so far, the best way to clear my negative thoughts is with simple meditation. Can someone suggest some simple meditation techniques that are easy and will take only a few minutes each day