3-1 is a pretty hard stage. However, these are the ways for you to turn the man into a dragon and earn that gold crown.
Set 1: Large Potion, Green Potion, Winged Potion
Set 2: Use Green Paint, Grow Gun, Place Wings on the man.
Set 3: Use Green Dye, Grow Ray, Place Dragon Wings on the man.
Scribblenauts Remix 3-1 Cheats Hints gallery:
3-1-1-a: Potions with adjectives will change any objects they are used on. Use potions on the man to give him the qualities of a dragon!
3-1-1-b: Give the man a green potion.
3-1-1-c: Give the man a large winged potion.