Making a start
Tools for the job - Get all your tools together before you start. Having a good paste table, a pasting brush, a sponge, a plumb bob, a tape measure, a sharp knife, a pair of decorating scissors and a bucket of clean water will make the job easier and quicker.
Strip away old wallcoverings by soaking with wallpaper stripper or warm water and detergent. When fully saturated, scrape off with a stripping knife. Make sure all traces of stripper or detergent are rinsed from paintwork and wash your hands thoroughly.
Should you find the wallcovering difficult to scrape off it is probably because the surface is, at least partially, impervious. Painted woodchip, embossed and washable papers can be particularly stubborn and are best tackled by scoring with a knife or wire brush before soaking. If you have a large area to work on, consider using a steam stripper.
Vinyl wallcoverings and peelable papers can be removed by pulling away the printed top skin whilst dry, then stripping the backing paper by soaking (see above). If the backing paper is firm, you can leave it as a base for the new wallcovering - but you must make sure it really is well stuck down, otherwise blistering could result.