Light strategy: Pick a warm white or barely-there neutral (Cloud White OC-130, Pale Oak OC-20) and paint walls, trim and ceiling the same color. The lack of contrast removes visual borders and the room reads as one open volume.
Dark strategy: Pick a deep, moody color (Hale Navy, Cheating Heart, Black Forest Green) and again wrap walls, trim and ceiling. The walls visually recede into shadow and you stop perceiving the boundaries.
What doesn't work in small Ottawa condos and powder rooms: a medium beige with bright white trim. The contrast emphasizes how small the room actually is.