Simple Miter Frame

• For small windows that aren't a centerpiece of a room--say, something in the laundry room or along a hallway--simple is sometimes best. A basic four-sided molding with mitered corners (like a picture frame) is a good answer here, and is easy to make yourself. All you have to do is measure the inside spans of the area to be framed, then use a miter saw to cut your pieces with outward 45-degree miters on each side to make the corners. This an especially good plan if it is a high window, as all four sides are the same design.
  
  

Corner Blocks

• This is a great trick if you don't have a miter saw handy (or just aren't confident in your ability to get the mitered corners right), and it also allows you to dress up the frame a bit: Buy pre-milled wooden corner blocks for the top two corners of the window (or all four corners, if there is no sill at the bottom). These are flat, square pieces of trim, usually with a circular pattern or other design cut into them. You nail them so they are sitting off the outer corners of the window, then run your trim up against them on the bottom and across the middle. It is the easier kind of window trim to install, but doesn't look that way.
  
  

Getting Fancy With Crown Molding

• Nothing looks better on a big, central window than classic crown molding--and nothing is more complicated to install. Crown molding sits out from the flat vertical surface of the frame, leaning forward at an angle. It has to have a nailer behind it to hold it out, and if it is cornered at the edges, then you'll need a compound miter saw to make the double-angled cuts. Don't try this if you haven't had some trim work experience, or at least can get on-site advice from someone who has some expertise. Once you decide to go with crown molding, you'll need to dress out the rest of the window as well in wide, sculptured trim and a presentable sill to carry off the whole classic look.