"Do want!"

Your character wants something. Anything. Universal peace. The boy next door. The griffon egg at the pet store. A cherry pie like mom used to make. The last digit of pi. Faster than light transport. A glass of water. As grand or as simple as you want it to be.

There are, of course, obstacles between your character and what he or she wants. Want and obstacles are the cornerstone of fiction :-)

It can be a new character or an old character you want to discover more about.

Start writing. Let the words flow without worrying about quality or whether it makes sense. If your character changes wants in the middle, go with it.