It is not possible to control the elements.
While it is possible to imbibe your workings with the attributes of said elements. It is beyond physical possibility to manipulate the tangible forces of an element(making water move or summon fire).
I will not go to far into this because you can find a number of posts on this topic.
If you wish to learn more about the elements AwakeTooLong published a lovely and very in depth article about the subject: http://www.spellsofmagic.com/read_post.html?post=548077
As Gekko has said, no matter how powerful the mage, they cannot control the Elements. The best we can do is to work with them in our magic. The Elements are too powerful and wild to be controlled.