make the mistakes on/with a prototype. Lumber and ply for a project is expensive both in dollars and time to acquire. Make a prototype from scrap and leftover ply and refine the details of a project before the BIG dollar workpieces are fabricated. A benefit might be that you wind up with another piece of shop furniture or some really neat features that were not in your original design. Here is an article and a short (1 min+) vid.
http://www.popularwoodworking.com/woodw ... h-the-workhttp://www.woodworkersjournal.com/benef ... -prototype