Before you begin...
Remove a small section of the wallpaper in an inconspicuous corner first, using a scraper (if you're lucky, there won't be too many layers). This will give you a better idea of how much time removing wallpaper is going to take and if necessary, you can change your plans.
Is it strippable?
Many wallpapers are "strippable," which makes removing wallpaper a much easier project. Pry up a seam edge using a utility knife and tug gently, pulling down at an angle, keeping both hands close to the lifting edge. If it comes off easily, peels in a long sheet and leaves no adhesive residue, then your job will be a simple one-step operation—unlike these home improvement projects you should never do by yourself.
Soften the paste
Soak older papers and newer ones applied with standard wallpaper paste. It'll make removing wallpaper go much faster. Use warm water and liquid detergent and add a handful of cellulose paste to each bucket of water—it helps to hold the water on the wall. Leave it on for at least 5 minutes, then use a scraper to lift off the paper. Score washable and wipeable wallpapers with a serrated scraper (or an old dinner fork), so that water can penetrate.
Remove wallpaper that's been covered with paint using a chemical stripper designed for textured coatings—but don't forget to wear protective gloves and goggles. You could also try fabric softener; removing wallpaper is a snap with fabric softener! Just stir 1 cap-full liquid softener into 1 quart (1 liter) water and sponge the solution onto the wallpaper. Let it soak in for 20 minutes, then scrape the paper from the wall. If the wallpaper has a water-resistant coating, score it with a wire-bristle brush before treating with the fabric softener solution.
Consider using a steam wallpaper stripper to tackle materials that are difficult to remove, or if the wall is covered with layers of old paper. It may make your job faster and easier.
Vinyl makes your job easier
Vinyls are usually easier to strip off a wall—the vinyl skin can be pulled from its backing, then the backing soaked away. With some modern papers and vinyls, the backing can be left on the wall as the lining paper for the next wall covering. This only works if the paper is well stuck—if there are any loose areas, strip them off.