You can use a template or use a strip piecing method. Just remembrt that part of the diamond will be on the bias and I would recommend to limit the handling of these pieces. They stretch and distort easier than a straight cut.
Try a few pieces before cutting all of your stash.
I cut a Lone Star quilt and it is very important to keep checking the alignment of your ruler. Particularly on angles, the ruler can slip and mess up your diamond.
Go slow and deliberate and you will be OK.