Go with light colors (light gray and white) for walls and trim, are a good choice and very popular right now. If you have the ability to do so, paint the cabinets a high gloss white. The gloss reflects light which makes the room look bigger. Uplighting wall sconces can also help as the light they cast upwards reduces the visual ceiling line -- giving the impression of a more spacious room. Use other reflecting materials if you can -- glass tile backsplashes are great! And, minimize the use of contrasting colors, which tend to make things look crowded.