Actually, it has worked for me in many ways. I too have long believed that my thoughts shape my life but only in the past year or two have I been trying to consciously channel my thoughts into a certain direction to achieve a certain thing.
Overall, I've attracted a lot of very positive things into my life. I feel that keeping positive thoughts and focusing on certain goals and attitudes has helped me tremendously.
I do find tho that I have to keep reading about the law of attraction and consciously focusing on it because sometimes my thoughts just kind of naturally go back to their old, more negative patterns.