You need to block it. Here's a tutorial:
http://fabricbias.com/2008/11/quilt-...hort-tutorial/
Edit: Crinkling depends largely on the batting you used. If polyester, you won't get much of any crinkling because polyester batting doesn't shrink. If cotton, you are likely to get some shrinkage. To keep shrinkage to a minimum, use cold water and dry flat after blocking. Most of the shrinkage occurs from the heat in a dryer.