Another good type of garment for practicing on are pajama pants or shorts to sleep in. You can get some flannel with a fun pattern on it, and there are usually only 2 or 4 pattern pieces that you'll need.
More info on buying and using patterns: http://www.cosplay.com/showthread.php?t=242887
Pictures and tutorials from my costuming portfolio at Syagria's Cosplay Site!
Star Trek Original Series Uniform!
Original Creation for AB13
Most Recent Con:
PAX East, Anime Boston 2013