I just moved into an old fixer-uper that my boss bought and our painter gave me a great secret! Use a spray bottle and spray a section of wall paper at a time, like a sheet at a time then peel off the top sheet. The top sheet comes off easily and what you have left behind is the backing to the wall paper. Next you use the same technique with the spray bottle and then a putty knife to gently scrape away the paper backing of the wall paper. This worked excellently for me, but I must tell you I was working with a plaster wall and not drywall.