Test Drive Colors
Paint can make a big difference—it's best to give them a trial run before bathing your walls. To do it, buy a quart of each color (Benjamin Moore sells sample-size jars for some colors) and use a brush or small roller to paint a 2" x 2" square on a clean (preferably) white wall in the room you intend to paint. Allow to dry, and then add another coat. You may want to paint multiple swatches in areas with different light. After living with the color for a couple of days, you'll know whether you want to commit.
Buy Matching Primer
When painting with bright or dark hues, ask the clerk at the paint store to tint your latex primer to match. You'll get better coverage and truer color, with fewer coats.
Shift Your Sheens
Consider using a shinier finish paint, like eggshell, for the darker or brighter color, and flat- or matte-finish for the lighter color. The flatter the paint, the harder it is to maintain (you can't wash a flat finish), but the variance creates a cool textural shift as you walk from room to room.
Watch The Line
Be sure to get a clean, sharp line where the two colors meet. To do so, paint the lighter-colored room first. Wait until the paint is completely dry (several hours at least), then carefully tape off the edge using easy-to-remove painter's tape. After painting with the darker color, allow it to set but not dry before peeling off the tape. Now, carefully clean up any bleeding paint with a barely damp rag.
