Quilt Patchwork Patterns - How do I make sure my quilt will be square when Im finished?

How do I make sure my quilt will be square when Im finished?

I finished a long time quilt project and was dissapointed because it wasnt square..I used polyester material and a quilting frame..

The best way to ensure that your quilt is square, is to square up each block as you make it. I do this by either cutting it after I have completed the block or by ironing it into square (pin it in place, then lightly press.) After you all your blocks are sewn together, square it up again. After you put on your borders, square it up...again!! If you are meticulous, the quilt will be square! Best of luck to you.
The next time you quilt, don't use polyester. Cotton is much easier to work with, keeps square without stretching, and it can be steamed into shape. Poly has a mind of it's own!
Next time, "square up" each block by checking to make sure they're not larger than they're supposed to be. I do this by using june taylor square rulers. If I have any excess on a block, I use my rotary blade to slice it off. Also, make sure you're consistent with your seams and always try to sew as straight as possible. If it's not that noticable, I wouldn't worry about it. My motto is "only God is perfect." I think mistakes or goof ups add to the character of the quilt. If I didn't, I'd drive myself crazy with all my mistakes. LOL. Good luck!