Camoooo...
Ninja camo method: I shake my head from side to side very fast. Then, when I hear my brains rattling, usually I see the nicest camo patterns...
Jokes apart, you can get really great camo patterns with Krylon camo paint and ferns, branches and various leaves used for masking.
First, degrease the parts to be painted with brake cleaner (do this outside, please).
For painting, start with a solid background color then use other colors with some materials for masking. Allow to dry overnight for every layer then go over the preceding layer with another color and masking material.
When objects are put directly in contact with the surface to be painted, the patterns are very sharp. When held a few inches away, the patterns get fuzzier. Try to strike a good balance between sharp patterns and fuzzier ones, the results might surprise you.
Better, try these techniques on a piece of cardboard before doing the gun.
Once the layers are finished, let dry a few days, very lightly scuff the surface with 0000 steelwool and apply a matte protective clear lacker over the works. Two coats wil do.
Good luck!
PP.