I just put my garden to rest for the winter, but it's never to early to start building your beds. I personally order my beds to be custom built by a local architect.
I make him go out to the pile of debris that was once a shed until a big wind done knocked that shed right on its keester. That world famous architect caresses each piece of lumber until he finds just the right one to salvage for our beds.
Here's the raised bed I built today and just for kicks I threw in some green lettuce. Hahahahahahhaaaa! Oh, slay me.