For butt joints, lay out your lines, and place the tape directly over them. I do this over a primed, ready to paint, airframe. I use automotive high build primer and give the lines two good coats. When the primer sets up, but isn't fully dry, I pull my tapes. After the primer is fully dry, I give the airframe a light sanding with 400 grit to get rid of any ridges.

I find that if you wait until the primer is fully dry, that I run the risk of tape, and tape residue, being left behind on the airframe.

Overlap panels take some planning. On a fuselage you have to start at the bottom, and at the rear. Tape is placed on the rear/lower panel, and paint is built up on the forward panel. An airbrush is excellent for this type of work. On wings, I start at the most rearward panel. If you have long, straight lines you can paint more than one panel at a time. I work in one axis at a time. On a wing, I start span wise and work towrds the leading edge. Then I start at the wing tip, and move to the wing cord..

This may explain it a little better. I go through the process, with pics, starting here: http://www.rcgroups.com/forums/showt...005782&page=74