I've had that happen too. It could be that the paper is too wet, it could just be the type of paper it is, or it could be that the blade is not sharp enough. In any event you do not want a jagged edge so what I do is apply your paper in place with excess paper along the top, then mark a crease with my fingernail where the wall meets the ceiling. Then I gently peel it away from the wall so that I can cut it with sharp scissors. When cut, apply it to the wall. You may need to add a little more paste along the cut edge.

Tack the paper to the wall before pasting and trim it. The tack holes will not show if you don't do many and only at the top and bottom. Push pins are excellent. If it isn't perfect, don't despair, you will be the only one who ever notices. Nobody pulls out magnifying glasses to inspect your work.

Hi. I have just moved house & I am papering my daughter's room. I have managed to get one full wall done (the only one with no window or door on it). However when trimming the top & bottom the knife isn't cutting through the paper (just dragging it) which I don't want as it is going to leave a messy finish. Should I leave the paper to dry when it will be harder or is my knife just not sharp enough?