The bad thing with those diamond shapes is you have to pin, pin and pin everything. On one of the quilting shows I saw a while back, I believe it was an E. Burns show, she demonstrated the best way to pin these together. Basically, you put a pin 1/4 inch in the bottom piece up through where the seams come together, then put the same pin up through the top piece 1/4 inch in through where the seams come together. This keeps them from shifting as you sew.
This probably isn't a real great explanation. But maybe you can get the idea from it. It was probably one of those things you had to see to really understand. But hey, I tried.