A few things that help me not to mess up....
1. Sit down and read all instructions in the project you are about to embark on.
2.Make sure you have all the necessary tools and supplies.
3.Measure twice....cut once and if confused re-read instructions, then measure twice cut once.
4.I never start sewing the day I am cutting out the fabric. I find it very therapuetic in handling,measuring and cutting the fabric.
5.I keep everything for the project in a sterlite or rubbermaid tub with a lid.
6.If it is a large project, I fill plenty of bobbins before starting.
7.Always use the best fabric,thread,rulers,needles and sissors you can afford. Piecing and quiling takes a lot of time,so there's no point in being cheap.
Lastly, don't be afraid to make a mistake, we all do.Just enjoy this hobby. I just wished my grandmother,who taught me to sew, could be alive to see how the sewing industry has evolved. She would be speechless!!! Oh, 1 last thing,make friends with your local quilt shop,they will be your best resource.The Amish women purposely make a mistake in their quilts because they believe perfection is a sin. Trust me when I say that I have plenty of humility in my projects.Blessings, Nancy