• Before starting-Clean to maximize the adhesion of the paint. This needs to be done in advance of your painting as it often takes trim 2-4 hours to dry completely after cleaning. If you are repainting trim be sure to identify your current type of finish. Protect adjacent surfaces from dust, paint drips or splatters by covering with a tarp or other cover. Smooth the surface of the trim and properly repair chips, holes, dents and cracks. It is important to keep in mind that the finish paint will enhance all imperfections.
•  While painting-Be sure to use masking materials to achieve a perfectly straight line and paint with confidence. Prime all raw or repaired areas of the trim. Be sure that you choose the best finish paint. While you paint be sure to thin, condition, the paint and maintain a wet edge to reduce brush marks. And most of all be sure to properly use the brush for the best finish.
•  There are certain tools that can make the task of painting trim much easier. These tools may seem comprehensive but most can be purchased at your local hardware store for little money.

Utility knife Scrub pad and plastic pail. Clean rags. Putty knife Small 1 inch paint scraper 5-way or 11-in-1 multipurpose knife Good drip less caulking gun Sanding pad or sanding block. Medium-Fine grit sanding block is the most versatile. Dust mask and eye protection. Rubber gloves Masking machine complete with masking painter's tape High quality brushes. 1½ angled sash brush for crisp sharp lines and 2 or 2½ inch square edge brush for painting flat areas. 

• Keep in mind that you can paint new trim before it is installed. This is often easier in a logistics sense as well. It can then be touched up once it is installed.
•  Whether you are applying two coats of semi gloss or gloss paint to your trim, you can ensure a good bond by sanding lightly between coats and wiping the dust off with a tack cloth.
•  When you begin to paint start with trim that is closest to the ceiling, and work down. You can then paint your door and window trim and frames, as well as any cabinets, either before or after you complete the baseboards.
•  A flexible edge guide is a necessary tool for painting the baseboard below the carpet line. If you have a very tall baseboard that has a wide, flat surface topped with a molded trim, you should first paint the molded edge with an angled sash brush.
•  Many people find the most difficult part of painting trim is keeping it off everything else. The extent of covering and masking depends on the amount of sanding and your expertise with a brush. If you will be doing a lot of scraping and sanding make sure to cover all furniture with lightweight plastic and the floors with drop cloths. If your needs are very minimal you can use a drop cloth where you are working. A runner may be all you need. Masking paper (available at your local hardware store) can be used around the bottom of door frames or anywhere you need some extra protection. Protect your floors with masking tape and paper to prevent drips and splatters. This will speed-up your brushing when you are actually painting the base trim.