ok, starch your pieces before sewing them. that should help.

Nativetexan is right, totally forgot to tell you that.

cconsider patchwork like a jigsaw puzzel. If the pieces are not accurate they won't fit the space and produce the final picture.
Yes, the squares MUST be accurately cut as well as all other pieces in the block.

I find that often the problem in accurate piecing is the first 1/2" and the final 1/2" or so inch on the seam is a problem. Slow down and watch these areas to be sure your seam remains consistent. Also......are you pressing or "ironing" Ironing can stretch. Pressing is up and down with the iron. Care is essential. Also when piecing triangle shapes, be sure when they are joined to other shapes you have the 1/4" at the ends.,

hello, I have looked at paper piecing see how it could make it accurate. l don't see how to press the seam to the dark side. i just sewed it to the paper.

I've done this block before without paper piecing and it was one of my first. I learned a lot about accurate seaming and squaring. You might be needing to use a stylus or a bamboo skewer to help guide the fabric through the feed dogs at the end of your seams (this is where I found I was getting "off"). It also helps to use a "leader" which is a piece of fabric that you sew over before your actual block. I found it helps keep the beginning of your seam more accurate.

Square at every round. Use starch to stabilize the bias and PRESS don't iron because ironing will distort the piece. It will save you a lot of seam ripping in the end. I hope this helps you.