How do you blend new car paint into existing paint?

depending on the color, you apply 3 + coats thinning out your base coat as you go. apply until you have near total coverage on the repaired area, and then start stepping out your spray whipping your wrist out away from the repaired area. Some colors are near impossible to match perfectly, like some silvers and golds, and pearl tri coat jobs are a whole different animal. with a tricoat pearl job, applying the proper base coat hue before applying your mid coat pearl is the secret. the goal is to fool the eye, and find possible "breaking points" on body lines etc. to "hide" your blend. paint manufactures make products called base coat blenders, which are used to burn in the edge of your blend and help it to blend in with the existing paint. once blend is complete, clear the entire panel, and your good to go. good luck, cuz it ain't easy : )