Painting can be an enormously satisfying job for the result that you will see when you are finished. However, preparation is very important to ensure that there are no messy and hard to remove mistakes.
To prepare your room, remove everything, including curtains and blinds. If this is not possible push all furniture to the center of the room and cover it with old shower curtains or sheets. Cover the floors with tarpaulins or thick canvas. Use masking tape to tape down your floor covering. Roll the masking tape out across the floor and the wall where you will be painting. Use masking tape also to cover any skirting boards, door or window frames. Masking tape can make your job so much easier, as you will end up with a good clean line when you peel it off. Just be sure not to wait too long after finishing your painting to peel it off as it can cause dried paint to peel.
Wash the walls using sugar soap. This will remove any grease or dirt. It will also help you identify any other imperfections which you may need to touch up. If previous paint is peeling, scrape the surface back and sand it until smooth. If there are any cracks, these should be filled using premixed filler and sealed using an acrylic sealer undercoat. Once this has been done, sand the walls until smooth and wipe away any dust with a dry cloth.
When choosing your brushes, be sure to check out all the options available to you which may make your particular situation easier. There are many different styles of brushes and in particular some which are designed for sliding along difficult to paint corners. Brushes and rollers should be chosen for quality, it can be quite frustrating trying to pick away loose brush hairs from your freshly painted wall.
Once you are certain that your surface is clean and smooth, you can begin painting. When applying the paint begin at the top of the furthermost corner from the door and work your way down and back. When using a brush, a diagonal crisscross pattern is the best, rather than straight up and down. Be methodical and pedantic to ensure that you get the most evenly spread surface. Be a perfectionist, fixing each problem as it comes up. Depending on the original colour of the wall that you are painting, you may need two or even three coats.
You may wish to experiment with a different paint finish. These are applied after your base coat. One popular paint finish is sponging. To do this dip a dried sea sponge into paint and dab it on the entire surface of the wall. Another method is rag rolling, where you apply paint rolling a paint covered rag across the wall. Combing can be quite effective, but requires some concentration and coordination. For this method cut even notches into the edge of a squeegee blade. Paint a coloured glaze over your dried base color and draw the squeegee blade through the glaze. These types of finish are best achieved by two people working together, as you often need to work fast after the gloss has been added, before it has time to dry.