The interior of your home is more than four walls. However, walls are possibly the biggest and most common surfaces you're likely to encounter when making some quick fixes to your home. You can make a dramatic change in the appearance of an interior simply by adding some paint to one or all of the walls in a room.
Paint an entire wall before taking a break so the painted portions won't lose their wet edges. Then stand back, scan the wall, and cover any missed spots or smears. Whether you paint in sections from top to bottom or from side to side across the room is up to you. But if you're using an extension handle on your roller, you may find it more convenient to start at one high corner and go all the way across the room with a series of completed zigzag patterns. This way you won't have to constantly change the handle on your roller as you would if you painted in sections from the ceiling down to the floor. If you're right-handed, start in the room's left-hand corner; if you're left-handed, start in the room's right-hand corner.