Hee Hee! I paint my bottom of the hull first and the waterline last, man I must be a warped. Partially because its easier to do without the guardrails and other little details I paint on the upper hull.
I paint with artist acrylics, which will come off if you sneeze too hard.
However, I like them because they are cheap, very easy to mix and use, are non-toxic, and I can make any color possible.
I find that no matter what brand of acrylics used, they work so much better on a primed surface. So I always prime my hulls with Krylon basic epoxy primer. However, always do a test spray first since I have found that some plastics, like Trumpeter uses, may react to the primer.
I give the painted surface a coat of Future or satin clearcoat protect the paint from scratches and lifting when masked. Like what was said, the clear coat makes for a smoother surface thus eliminating low spots that can cause bleed.
Tape I use is 3M painters tape for large surfaces, drafting tape for areas that require very little tack, and Tamiya tape for really small details such as doing a "dazzle" cammo scheme.
Painting hulls can be a lot of fun with some creativity.
Scott