There are some wonderful books out there -- my favorite authors are Marsha McCloskey and Jan Krentz. Both of these women have authored great books with step by step instructions and lovely inspiration. They also offer special rulers, but I make my stars with my trusty old 6 x 12 or inch ruler.
Unlike a lot of machine pieced stuff where you cut everything oversized, sew it together, then cut it down to make it accurate, I find that accurate cuts and then careful sewing works best for this. Because of the bias edges on the diamonds, it's easy to stretch them. Then the points get cut off when the block is squared up. Starch or sizing on the fabric and careful pinning and stitching eliminate this problem.
Placing the ruler with the 45 degree mark on the edge of the strip, make the first cut. Then move the ruler until the one and three quarters (1 3/4") lines are along the cut edge and cut the diamond.
You will need eight diamonds for this. I stacked the red and black strips and made four cuts for my eight diamonds.
The larger square is for the quarter square triangles. Set it on the cutting mat so that lines extend from each corner and without moving the fabric, make two cuts perpendicular to each other without moving the fabric.
Mark the points of the diamonds (at the sides) and the points of each background piece where it meets the inner part of the diamonds.
I used my chalk pencil on the dark fabrics and a blue washout pen on the light fabrics (click on the photo to see the dots more clearly).
I left the photo large, so by clicking on it, the measurements will be obvious. I would give credit to whomever thought this up; but I received it such a long time ago, I can't remember where it came from.
The reason for arranging them into these piles is because it makes it much harder to get confused and accidentally sew the wrong diamond to the wrong background piece and wind up with this:
Then I pin all of the diamonds to their respective background pieces.
First I poke a pin through the dots and line up the edges. For the diamonds sewn to the triangle pieces, the narrow points should line up exactly.
I hold the pin straight up and down between my index and middle finger and carefully slip in a pin on each side of the first pin. Then I remove the first pin and poke it through the diamond/triangle point to hold that together while I stitch the seam.
I use silk pins that are very thin and strong.
After I have pinned all the diamonds to the background pieces, I take them to my machine to chain piece.
Next: Stitching and pressing the Lemoyne star.