Scrape off loose texture with a putty knife or floor scraper
Repair dents, gouges, and damaged drywall with joint compound
Sand the wall smooth after repairs dry
Apply a skim coat of joint compound over the entire wall
Let the skim coat dry completely
Sand the skim coat smooth
Repeat skim coating if texture is still visible
Prime the wall with a drywall primer
Paint the wall after priming
Use drywall replacement if the texture is too heavy or damaged to skim coat
Hire a drywall professional for large or difficult areas