The easiest, most pain-free way to do a lap size Lone Star is with the Quiltsmart interfacing.
http://www.quiltsmart.com/khxc/index...38inchlonestar
No diamonds. No angles. No bias edges.
This star finishes at around 36" plus whatever borders you want.
They also have a 58" star if you want it larger. Same concept.
I love this method! And it's worth the money.
If you do want to buy a book and/or make using a more traditional method, Jan Krentz's Lone Star and Beyond had fabulous detailed instructions and photo to help you avoid any pitfalls.
http://www.amazon.com/Lone-Quilts-Be...4639737&sr=8-1
My first one was via Jan's method, and the rest have been with the interfacing. But I prefer Jan's method of finishing the star square.
And the book can sometimes be found on the racks at Joann's, so with a coupon......