I'm new so I have limited advice. I like to use spray adhesive like 505 or June Tailor for all layers; I think though if I ever did a large one I'd also do pins to make sure it held. That leads me to the other thing; you'll notice as you go you are going to have to stop all the time to remove your pins as you go; try pinning inside of the blocks so you don't have to remove to many pins; it'll go faster and less frustrating to constantly stop to remove pin. For your first quilt you did a great job; no one could tell you are a newbie by this one.