Pretty much what la0o9 said.
Either come up with an original plot you would like to make reality or solve problems you have with current principles and techniques out there. However, I would always suggest to look at it from a 'problem solving' perspective because if there is no problem to solve, there is absolutely no need to come up with anything new either.
Keep in mind that being a magician is not about creating new tricks. Most magicians survive merely on other people their creations which they made their own with their performances.