I would practice with the comfortable ribbon, whatever that one was for the particular bow I was trying to learn. And then start doing them in different sizes/widths.
One of the gals on here has a wicked sale going so I was able to get a lot of ribbon at a great price for more variety. I've got a craft show coming up so that was my motivation but with shorter lengths there you can make some for your kiddo and sell the others so it's not 5 yards of the same bows =)
Let me see if I can find that thread and I'll edit my post to link it here!
*eta* couldn't find the thread but here's her etsy. very fast ship and well packed, couldn't be happier with my purchases http://www.etsy.com/shop/RibbonColle...ef=seller_info