Sorry I do not have pics up right now, but I did a rattle can paint job on one of my fixies. I stripped the paint and roughed up the surface of the bare metal a bit with some steel wool. I then cleaned the frame with citrus degreaser. After the frame was dry I then cleaned it again with some plain water and dried it completly.

I used automotive paint for your engine block. Three coats of primer, and then 3 coats of base paint. I masked off the design and sprayed 3 coats of black. After peeling off the maskes I had some sweet green skulls. Then I let the paint cure, and I sprayed on 5 coats of clear. It took forever, but here are some tips for better rattle can paint jobs.

1. make sure your frame is clean.
2. keep your cans in about 5 inches of warm water. (I just used a bucket)
3. spray lighter coats and wet sand them if you need to smooth them out 1000grit sand paper or higher can really shine it up, a bit lower to take out bumps, finger prints, and orange peel
4. Make sure you buy lots of cans of paint. Running out can cause a huge delay. It works out to 2.5 coats per can for me.
5. Slow and steady is the key to even paint, practice on something else first.