If you need inspiration for making a sig here's were you'll find some help.
This is what I do:
1. Figure out what characters you want on it.
2. Surf around for pictures and gather them.
3. Still need inspiration? Play around with brushes and settings to help you come up with the perfect idea.
4. Just start putting them together. Maybe something will come.
How do you other sig makers get your inspiration? :D