Before you even think about colors, you need to understand the room you're working with. How much natural light does it get? A north-facing room with small windows will make most colors look darker and cooler than they appear on a swatch. South-facing rooms tend to warm everything up. Spend a full day in the space if you can, watching how the light changes from morning to evening. That bright white you loved at noon might feel harsh and sterile under artificial lights at night.
The finish matters more than people realize. Matte paints hide imperfections well and give walls a soft, modern look, but they're difficult to clean. One greasy handprint near a light switch and you're stuck with it. Eggshell offers a slight sheen and wipes down easier, making it a solid choice for living rooms and bedrooms. For kitchens and bathrooms, semi-gloss or satin finishes handle moisture and scrubbing much better. High-gloss is durable but shows every bump and flaw in the wall, so unless your surfaces are perfectly smooth, avoid it.
When picking a color, start with what's already in the room. Look at your furniture, your floors, any artwork you plan to keep. The wall color should support these elements, not compete with them. Neutrals are safe but can feel lifeless without texture or contrast. If you want something bolder, test it first. Buy a small sample pot and paint a large square on the wall. Live with it for a few days. Colors that seem exciting in the store often become overwhelming once they cover an entire room.
Finally, don't underestimate the importance of proper preparation. No paint will look good over dirty, cracked, or uneven surfaces. Fill any holes, sand rough patches, and apply a primer if you're covering a dark color or painting over bare plaster. Cheap brushes and rollers leave streaks and fibers behind, so invest in decent tools. Two thin coats almost always beat one thick coat. Take your time with the edges. Rushing through the prep work is the fastest way to end up with results that frustrate you for years. And remember to ventilate properly while painting. Open windows, run a fan, and give the room at least a day or two to air out before moving furniture back in.