Touching up spots

I've sprayed my entire XJ before, and have assisted with painting several other vehicles. I've also done parts of other vehicles before, but I don't know how to blend a touch up with the rest of the surrounding paint.

How do you feather back from the spray area when you are touching up a small spot to get it to blend in with the larger surface? How do you protect the surrounding paint and not mask it off, getting lines where it was masked?

Thanks,
Geoff

If the touch up is small enough, I use a selection of camel hair brushes I have. A dab of rust inhibiting primer, a touch of color coat and then a touch of clear. Kind of like paint betweent e lines. Works better for some colors better than others. On white, you don´t hardly see it, on black maybe if you get just the right angle.
If it´s a larger area, I usuually just spray a section between a seam and and a raised line.
I´ve tried featherig in spots with an air brush, the color coat is pretty easy, the clear is some harder. 600 sandpaper (wet) for the edges of the color and polishing compound to feather in the clear. The results kind of depend on the color. The edge of the feather, often shows up, with the next wax job.
A different kind of paint, might be easier. But I´m always little affraid of lifting, if mixing paint types. Most of the newer paints don´t color sand well.
Clear coat, color sands and polishes pretty good.

Small spots/rock chips can be hidden fairly well like 8Mud suggests. If you are repairing a small dent or scrape first do the repair (bondo or fiberglass must be applied to bare metal) start sanding the repaired area with 80 grit paper. Use a bodymans "longboard" to do this and sand in several directions to "level" the repaired area. Spray 3 wet coats of primer over repaired area allowing each coat to dry to the touch. Put 400 to 600 grit wet/dry paper on the longboard and resand the area until the primer blends with the original paint. Using water to do this is easier to see what your doing, but you can sand dry if you want to. After the repaired area is sanded, sand the entire panel using a foam block with 600 paper (wet). Take your time and use short strokes. Paint (basecoat) and clearcoats will not stick to panels that are not sanded. The local carwash will blow it off. Spray the basecoat in light coats until repaired area is covered, working outward as it hides. When you cannot see your repair, spray further outward but don't cover the entire panel. This is known as blending. After it is dry, spray the entire sanded panel with 2 to 3 coats of clear. If your repair is next to another panel you will have to sand it before you apply basecoat. There are other methods to do this but they also involve sanding and using a buffer when finished.