Hello there!
You have probably already tackled this project by now, but just in case...
The trick to getting a seamless finish when using tisse paper is to tear all four of the edges of your square of paper. Don't allow the pieces to tear in a wave pattern -the edges need to be fairly straight. Be sure to overlap each piece onto the next by at least an inch, maybe a little more, so you don't end up with a "bump" where the two peices meet! Oh, and don't put it on the wall with wallpaper paste - use paint.
Amanda
www.artisticillusions.com