I print out the pattern and then I adjust it to the size that I want. I am very fortunate because I have a photocopier, so that allows me to mess around with the sizes.
Now if its a large pattern to cut I use painters tape on to the wood I'm going to use and then spray both the pattern and the tape so that it sticks good and I know it will stay there for as long as I want it too.
If its a small pattern I either put painters tape on the wood and then use a glue stick to stick it down or recently I purchased a roll of Scroll Saw Tape/Adhesive which I find very good. You can get it from, www.scrolleronline.com
Marg