1. Roll paint along the edges for consistent texture
Corners and areas next to trim that are painted only with a brush have a noticeably different texture than the surrounding paint. To ensure the finished texture will be consistent in these areas, brush on the paint, then immediately roll it out before the paint dries. Use a smaller roller with a nap that's the same thickness that was used for the rest of the wall. Roll as close as you can without bumping the opposite wall or slopping paint onto the trim. Finish brushing on the paint and rolling it out in one area before moving on to the next section.
2. Prime and texture wall patches to avoid a blotchy finish
Freshly painted walls often look blotchy. The colour is uniform, but the sheen isn't consistent. This usually occurs over the holes and cracks you patched with a crack filler. The porous fillers absorb the paint, dulling the surface (a problem called "flashing"). When light hits these dull spots, they stick out like a sore thumb. The smooth patch also stands out in contrast to the slightly bumpy texture of the rest of the wall. A quick coat of primer is all it takes to eliminate flashing and texture differences.
Primer seals the patch so paint won't sink in and look dull. To match texture, prime with a roller, feathering out the edges. Choose a nap thickness to match the surrounding wall texture.
3. Let paint dry, then cut the tape for a perfect edge
Once paint is dry, you can't just pull the tape off the trim. Paint forms a film between the wall and the tape, and removing the tape tears pieces of dried paint off the wall. So before pulling off the tape, cut it loose. Wait for the paint to completely dry, at least 24 hours, then use a sharp utility knife to slice through the film. Start in an inconspicuous area to make sure the paint is hard enough to slice cleanly. If you cut the paint while it's still gummy, you'll make a mess. As you cut the paint, pull up the tape at a 45-degree angle.
4. Feather out paint where you can't keep a wet edge
You can't cover large areas like ceilings, extra-tall walls or stairwells in single, continuous strokes, so the best way to minimise lap marks on these areas is to feather out the paint along the edges that you can't keep wet. The thinner, feathered coat of paint will avoid the buildup that causes the lap mark. This method also removes all the paint from the roller, making it much easier to clean.
To paint a large section without leaving lap marks, roll the nearly dry roller in different directions along the dry edge, feathering out the paint as you go. After completing the entire length of the wall or ceiling, move to the next section and paint over the feathered edges. For the second coat, apply the paint in the opposite direction. This crisscrossing paint application sharply reduces (if not eliminates) lap marks.
5. Use a drop cloth
Spills and spatters happen, regardless of how careful you are. It's a lot easier to prepare for them than to wipe them out of your carpeting or off your wood floor later. All it takes is canvas drop cloths in your work area. The canvas stays in place, so you don't need to tape it, and you can use it to cover any surface. Plastic drop cloths are slippery to walk on or set a ladder on and don't stay in place. Even worse, paint spills on plastic stay wet, and they can end up on your shoes and get tracked through the house.
But even with canvas large spills still need to get wiped up right away or they'll seep through. Clean spills with paper towels or cloth rags. Likewise, if you splatter paint on any other surface, wipe it up immediately.
6. Preparation is the key to success
One coat of paint usually won't hide the underlying colour and sheen on trim. And if you don't sand the surface smooth between coats, the finish may have a grainy texture. For a smooth finish, sand the trim before applying each coat of paint. Sand the trim with a fine-grit sanding sponge. Sponges get into crevices where sandpaper can't go and apply even pressure. Then apply the first coat of paint, let it dry at least 24 hours, lightly sand it again for a completely smooth surface, and apply the second coat. After each sanding, vacuum the trim, then wipe it down with a cloth to remove dust.
7. Mix several cans of paint in a large bucket for a consistent colour throughout the room
Paint colour may vary slightly from one can to the next. If you have to open a new can in the middle of a wall, the difference may be noticeable. Mixing the paints together eliminates the problem. It's best to estimate the amount of paint you'll need and mix it in a large bucket. When coverage is difficult to estimate, add more rather than less. You can always pour the leftover back into cans.
8. Clean dirty surfaces so paint can form a strong bond
Paint dirty, oily surfaces and the paint will easily chip or peel off. So before painting, clean grimy areas with sugar soap or cleaner intended for prepaint cleaning. They work well to clean painted, varnished or enamelled surfaces to improve the adhesion of the new paint. They're ideal for cleaning greasy or oily areas like kitchen and bathroom walls.
Wipe on the cleaner in a circular motion using a lint-free cloth or abrasive pad. Start at the bottom and work up. After the surface is clean, fill in any nicks and holes, then sand them smooth before painting. The cleaners are available at paint and hardware stores.