Just take a small razor cutter and slice a semi circle over the top of where you’re going to put the nail or screw. Then gently pull the flap to expose the wall and drive the nail in. This way, if and when you remove the wall hanging, you can easily glue the small flap you created to conceal the hole back up and it won’t be as apparent.
I had never thought of this before, and when I lived in a house with more wallpaper, it sure would have been handy when we went to move for the next owners!
Also, a different way to handle an edge when you get to it but will only have a small sliver of wallpaper or difficult area around a window or something (and your wallpaper has a smaller or no pattern), then you can actually work a full size piece from the end into the other piece, but before adhering to the wall, you just take a metal yardstick and cut with a sharp razor, cutting through both pieces and then remove the excess on both sides, and -poof- you have a nice clean seam moved over.
Feel free to post and share your ideas!