Might as well throw this in on the basis of Magical Laws for Writing according to Brandon Sanderson:

[quote][i]1. Err on the side of Awesome
2. An Author's abilities to solve conflict with magic in a satisfying way should be DIRECTLY PROPORTIONAL to how well the reader understand said magic
3. What the magic can't do is more interesting than what it can do
4. Expand what you already have instead of adding something new.[/i][/quote]