Hi Stephanie - I've been quilting for close to two years now and have documented info about all the quilts I've made. I take pics along the way, keep track of patterns used, fabric used and yardage, batting, threads, needle type, techniques, final quilt size, type of binding and anything else I think is pertinent. Example: I've cut and pieced fabric differently (than the pattern called for) to save fabric waste or enlarged a pattern and made note of that for next time. I print and keep pics in a binder with all of the other typed notes stored on my computer. I've already referred to the info on several occasions when planning another quilt. And it sure is fun to flip through the binder to see what I've made since almost all of it has been given to family and friends.
I highly recommend keeping track of what you've done and organizing pictures at least - it's rewarding to re-visit the pics and very helpful (for me) to look back at my notes.
Good luck with whatever way you decide works for you!