There are some really fine pins you can get from Amazon (can’t find them anywhere else). Clover Extra Fine Patchwork Pins. Using the directions given above by Jennifer23, I would also have the seams pressed and then draw the 1/4” stitching line on the second pieced parallelogram you are adding to the center strip. Use 1 pin to line things up. Stick the one pin straight through where the seams should line up on both pieces. Then use another pin to hold the pieces together as you usually would. I usually use a pin on either side of first one before removing it. // I have tried just using one pin and then after matching the intersections on each piece just tipping the end of the pin into the fabric but I was always a little off when I tried that. // The first method gives me the best results. Just took a few tries to teach my hands how to hold things.