You can trim the pile evenly, but it is difficult to get it perfect. My preferred choice would be to find fur of the correct pile height. Either way here are some tips and tricks:
1. If you decide to cut the pile, lay the fur down on a flat surface where you can work on the entire area (or a large area) at once.
2. Use flat surface shears if you can get ahold of them (like these:
http://www.fiskars.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10101&categoryId=10268&productId=10500&page=products ) Usually a gardening product rather than a craft product.
3. When cutting your pattern shapes, after the pile is the height you want it, turn the fur upside down, and trace the pattern on the back with chalk. Then cut the pattern out with an X-Acto knife. This prevents you from cutting into the pile and damaging the fur on the edges.
Hope that helps.
smile