So I know personally that making magic systems is my favorite part of writing fantasy. So I thought I'd share the inspiration. All you have to do is create a magic system for any world. It could be our world or any fantasy world you created. It could be based in the four elements, on emotion, or really anything. Just really get creative and have fun with it. Describe how your magic system functions and answer some basic questions like:

-Who can use magic? Are they called witches, warlocks, what?

-How is it used? and for what purpose?

-Where does it come from? What's the source of the Magic?

-What are people's reaction to magic? Is it outlawed? Is it used in daily life? 

Of course you don't have to answer all these questions( unless you want to). There just dare to get ideas rolling in your head. So yeah, really just have fun. I'm sure they'll be great.