How do they get such a clean edge ?

cutting in

Using a sash brush here, wall paint is cut in to the door casing.

 Although it is just one of many skills required to be a painter, the ability to cut in well is probably the most noticeable. This is an acquired skill not to be mastered in just one weekend, however some people will catch on to this very quickly, while others will need allot of practice. Then there are a few folks who will probably be to impatient, and not put much effort  in learning to "cut in", this group will fair better to hire a painter.

 Masking Tape

Of course masking tape may be the solution for some of you, and even many of the best painters use masking tape for different things but the ability to cut in with some degree of skill is an invaluable tool to anyone serious about doing much painting around there house. So even  if you are planning to use tape to make most of you're paint lines, Try cutting in with a sash brush from time to time to help you get the knack of it.

TV Tools
You have probably seen some of these nifty devices on television and in department or dollar stores. The goal of these products is to make the job of cutting in easier. As there are numerous different products out there we can not really advise you as to just witch of these things will work for any given situation, so if your interested in one of  these nifty looking things... give it a try.