Morganfam7, I looked for a video of the method I use, and this one is the closest. It's a Fons and Porter video, so there is a plug for their products. I don't use the F&P ruler used in the video, instead I mark a line along the diagonal center and sew a quarter of an inch away from it on each side. Watch the video and you'll see what I mean.
https://www.youtube.com/watch?v=k-nme6km8h8
Here's a tutorial from here that is similar, but produces many more blocks. The theory is the same, but multiplied. This shows the marking method I use.
http://www.quiltingboard.com/tutoria...s-t141047.html
Tate