K.R.
Hi K. ~
I used stick on borders for my kid's rooms because I wanted to be able to easily change it as they grew older. I didn't have a problem with it falling off.
I would say, just make sure the wall is clean and dry when you put it up. If you still have the problem, try using rubber cement (available at Michael's or Ben Franklin's). You put a thin layer on the back of the pattern, then a thin layer on the wall (try to keep it somewhat within the space of the pattern). After it dries on both surfaces, you stick the pattern to the wall. If there is any glue left around the edges, just rub it off the wall. When you want to remove it, just gently pull it off the wall and rub off any leftover glue. Good luck!
~ K.