The problem with doing anything having to do with control of the elements outside is, while having it work gives you a great boost of confidence, as Kikuyo mentioned, it can easily be attributed to nature.
Try it inside. Concentrate and do the same things as you would outside. You will have a better awareness of it it's YOU creating the wind, or Mother Nature herself.
Be aware of your surroundings too. I once made a candle flame go out and got really excited....until I noticed my ceiling fan was on =(