To add a certain amount of depth, or random look, to drywall, many people like to use an easy to apply knock down texture. This knock down texture is sprayed on and gives a smooth wall a rough texture with different levels and uneven surfaces. The best part of applying this type of wall finish is that there are no exact rules. It can be done according to the whim of the homeowner. However, when getting close to corners and windows there are some steps to follow.
Step 1 - Protect Windows
Spraying the joint compound onto the wall does spread over the area and leave small spray onto trim and other areas where you don't want it. Protect windows, trim, and sills by covering them with a plastic sheeting. Use painter's tape to secure the plastic and protect the drywall underneath.
Step 2 - Spray Carefully
When getting close to a corner, angle the spray gun towards the wall and away from the corner. The gun should be about 6 to 8 inches from the surface of the drywall, but at an angle. As you spray the wall move the gun from top to bottom and back up along the same path. This will keep the spray in a straight line without worrying about spraying items around the corner.