When it comes to home improvement projects, painting generally falls in the fun category (as opposed to, say, updating plumbing). But that doesn’t mean it’s easy. Choosing the wrong color or skimping on prep can turn fun upside down pretty quickly if you don’t follow some basic rules.

For pointers, I turned to interior designer Kenneth Walter of Gray & Walter, who just completed a glamorous model unit at the Ritz-Carlton Residences (it includes faux ostrich finish on the bedroom walls and a stunning black ceiling in the kitchen).

Here is what he had to say:

1. Be cautious—but not afraid—of dark hues.

“If you want to make a room cozier, go for chocolate brown or black lacquer. A black room can be traditional or contemporary. I love deep reds, rose, or terracotta for dining rooms and forest green lacquer for traditional living rooms. If the room or overall home is small, then stay on the lighter side to make the space appear larger. Light colors can also be soothing. My bedroom is tranquil and calm, with pale pink walls (think of the color inside a shell) and pale, mossy green trim.”

2. Don’t choose a color based on a small swatch.

“Buy a small can, paint a big piece of card board, and hang it on the wall. Look at it on a bright day, a gloomy day and in the evening. Colors change dramatically depending on the light source.”

3. Treat you trim right!

“Moldings and trim need proper prep—it may take two days of prep, depending on the size your project—and a minimum of two coats of paint. New woodwork needs a minimum of three coats. Take the time to find the right painter for the money you have to spend. And never paint woodwork with latex—use oil. It lasts up to ten years if properly applied. If the smell bothers you, buy the very best latex you can. Farrow & Ball has the best latex for trim.”

4. Think beyond white trim.

“White is most commonly used for trim, but I love old ivory, pearl, or pale grey. In general, for a traditional look, neutral is the way to go. For a contemporary look, try painting the walls and trim the same color. How about a gorgeous greige or light blue-grey for the entire room? All done in satin. In most cases, Benjamin Moore Ivory White (925) is my go-to trim and ceiling color.”

5. Consider your finish very carefully.

“A high-gloss finish should only be used when surfaces are expertly prepared. Otherwise, stick with semi-gloss or satin enamel for trim, doors and woodwork. Never use flat on walls in high traffic areas or if you have pets and/or kids. Most walls could benefit from an eggshell finish, which can be wiped. Satin is great for walls in high traffic areas, such as kitchens, mud rooms, or hallways. Use flat for all ceilings, except for in the kitchen and bath, where I recommend using eggshell finish.”