Before any work can proceed repairing the damaged drywall surface is the first step. If there is a hole in the drywall, repair it according to the tutorial Repairing a Hole in Drywall. If the damage is worn or abraded wall texture or a gouged in the wall surface that has penetrated the drywall face but has not created a hole, repair the area with spackling or redi-mixed wallboard joint compound before repairing the texture. Sand smooth and wipe the sanding dust off with a damp cloth.
Next we need to practice our texturing technique.