Here are a few tips on taping a two tone off;

1. Whether you use the green Fine line (better for long straight lines) or you use the blue Fine Line (more flexable and better for curves) don't stretch it out! If you stretch it, it will shrink back later and pull up from the edge. After you lay it down, take the back of your fingernail and press it down good. It will kinda change color, darken, when it is pressed down firm. BE SURE YOU DO THIS or it will let paint under the edge.

2. After you run your fine line tape on the edge of your second color, don't start your masking by taping over the fine line tape. Instead start just below it a half inch or so. At that point, go ahead and cover with paper or plastic all you plan on protecting. Now, your whole truck is taped up and there is a half inch gap between the masking papers last tape and your fine line on the edge of where you are going to paint your last color. Bridge those two with a 3/4inch regular masking tape.

The reason for doing this is that after you paint the clear you can pull up this 3/4" tape and then pull up the fine line BEFORE the clear is dry. The edge of the clear will flow over the edge of the base coat and leave a nice soft edge.

3. To lay a long, straight line, don't tape it a little at a time. Tape the front of the line over the adjacent panel a few inches, pull the tape off the roll walking back to the other end of the panel and put a LITTLE tension on the tape to keep it straight. Eye down the tape like a rifle of a gun. Then lay the tape all the way at the begining from the other end of the panel holding the tape roll out off the panel. When you have laid it down the whole length of the panel you will then be onto the next panel with your tape pulled out off the roll. You can continue or, cut it off at the end of the panel and do the same thing over again on the next panel. You aren't laying it all at once understand, you can hold the tape roll up high and only let the tape hit the panel as it is in the right position, just aim it like a rifle. I hope this makes some kind of sense.

4. DO NOT pile on the paint and clear. This is a death sentence for a tape edge. Take it easy, a few coats of reasonable flat clear is plenty to cut and buff. As long as you don't go nuts on the cutting, you will have the 2-3 mils recommended by most manufacturers.

Brian

Great advice Brian, That also works for general masking.
I find if I pull the tape while the clear is still fresh I get better
results for items like moldings and trim too.