The Best Tips for Cutting in Paint Where beginners run into trouble is cutting in along ceilings, moldings and other areas that require a perfectly straight line of paint. We'll give you some tips and pointers to help you increase the speed and improve the accuracy of your cutting-in technique. http://www.familyhandyman.com/painting/techniques/the-best-tips-for-cutting-in-paint
Here's the real trick for perfectly crisp lines: seal the edges of the painters tape with some of the base wall color before painting on the contrasting color. Don't paint the whole width of the tape. Just a bit along the edge of the tape on the side where the stripe will be painted. Let that paint dry and then paint your stripe color. great idea!