Here's a tutorial on making string blocks.
http://heartstringsquiltproject.com/guidelines.html
I usually use thin muslin or light colored fabrics for my foundation. After layering with batting and backing the quilt is a bit thicker than usual. Sometimes I skip the batting and use flannel for backing, great for kid's quilts. If you do want to use batting, you could use paper or deli wrap as your foundation, which you need to tear away before layering your quilt. May in Jersey