Cutting out a square:
When I lay the template on the fabric I make sure that I lay the template on so the dark lines cross where the light center comes to a point. This gives me a ¼” seam allowance above the point.
I use a mini mat so I can turn the mat as I cut.
Next thing I do is to center the bottom corner of the template. I look at the lines on the template and count the lines from the corner back to where the edge of the center is. Just count on one side and then find the same line on the other side. Now center so you have the same number of lines on each side of the bottom point of the template