FWIW, from my experience with two frames, one rattle can and one using automotive paints and Preval sprayer (you pour paint in to make your own spray can)

it is way more expensive than you think, in most cases you probably can get the frame powder coated for the same or less money.

Prep is every thing

More important than prep is wearing a good respirator

what I did
1. Strip frame with chemical stripper
2. make sure all the paint is gone, you will see anything left
2 1/2 mask
3. Wipe frame down with acetone or special paint prep.
4. paint with acid etch primer
5. paint with high build up primer
6. Sand smooth
7. Wipe dust off
8. multiple thin coats of color, follow the recoat times religiously
9. mutiple thin coats of clear