Before stripping the old wallpapers, it is always advisable to first peel off a small section of the wall paper as a litmus test to see if the wallpaper comes off easily. If it does you can very well carry on with stripping the entire wallpaper. In case the wall paper can be stripped easily, you should continue applying hot water on the wallpaper.
The hot water will wet the wallpaper and it will be possible for you to strip off the wet wallpaper easily. In some cases a mixture of hot water and vinegar is applied on the wall paper. This mixture is usually sprayed over the old wallpapers.
In some cases, a wallpaper remover is used in place of the water-vinegar mixture. You need to follow a specific pattern while removing the old wallpapers. For example you can strip the wallpaper from left to right, from right to left, from one corner to the other, from top to bottom or from bottom to top.