If you’re going to be applying wallpaper around sockets or switches, first shut off the electrical power to the room. After that, you should remove the cover (and any other external parts) of each socket and switch. You do not want to apply your wallpaper around these covers as it’s significantly more difficult. Think about it as if you’d be painting the wall — if you would keep the covers on and paint around them, not only could you get them dirty with paint, you would see a strip of the old paint on your wall if the cover would be slightly moved out of its place.
Once the covers are off, you can either apply the wallpaper strip to the part of the wall above the socket and let the rest hang loose for now, or simply place the wallpaper on the wall before the paste is applied and align it with the previous strip (do this when wallpapering around a switch or a socket that’s not near the floor). Either way, you can let the wallpaper strip hang over the switch/socket and find out where it’s located under the strip. Take your knife and carefully cut through the wallpaper at four separate points above the switch/socket near each of its four corners. Now, use your craft knife to cut horizontally and vertically from one hole to another, until you are left with a small cutout of the wallpaper strip. You can use a small straight edge to do this. This should allow you to be able to attach the switch/socket cover back with the wallpaper applied to the wall.
To finish off you have to apply the paste to the wall and around the coverless switch/socket, hang the wallpaper strip onto the wall, and place the cover of the switch/socket back where it belongs.
There may be other objects on the wall (such as thermostats or light fixtures) that cannot be removed for the wallpaper hanging. In such a case, proceed similarly as above to find out where on the wallpaper strip the object will be located. Make a small incision through the material, about half an inch long, at the center of the object, followed up by four cuts from the incision towards each corner of the object. You can use scissors to make the cuts if possible and you can make more than four cuts if this makes it easier for you to place the wallpaper strip around the object. You can now apply the strip to the wall — apply paste to the wall and consider using a small paintbrush to apply the paste around the small object. Once the strip is attached to the wall, use a small straight edge to trim away the loose parts of the wallpaper along the edges of the object.