I made over 2 dozen bargellos in my quilting life. If you are an organized person and pick out a simple pattern, you will be OK. It is when the pattern is complicated that it is so easily to make an error before you realize it. One of our board member posted this recently:
http://www.quiltingboard.com/main-f1...x-t261340.html
I am NOT an organized person so I rely on my design wall to catch an error I could easily make.