I am not much of a CAD person, in fact, most of CAD in the past has been done with MSPaint!

I have noticed a few on here donig some scale models of their TTT prior to jumping in, and I think that is the route I am going to take. However, I am always open for new ideas, and paper/pencil go a long way with me as well. For those that have made the scale models, where is the best place to get supplies, craft store or hobby store? Also, how do you remember what you did after you make the scale model, do you take notes as you go, or do you already have a predetermined plan of action and stick with it, only making changes as needed?