I purchase a lot of my stabilizer from All-Stitch. They have a great FAQ page:
http://www.allstitch.net/department/...info-10242.cfm
I particularly like the info in the stabilizers - embroidery backings
The best thing I learned in my training sessions was to make an informed decision on choosing an appropriate design in the first place. While you can add a ton of stabilizer to a thin cotton and do a stitch intensive design, it's better to choose a more sheer design and keep the bullet-proof ones for canvas bags.