it is best to put together some practice pieces and PRACTICE, PRACTICE, PRACTICE until you are comfortable with the process and happy with your quilting BEFORE trying to quilt your quilt!
start small (like a pot holder or placemat) if that goes well- try a baby quilt---when that's pretty good try a throw---ect----work your way up- each larger size is a whole new challenge---and no one can just decide they are going to (do something simple) and have it all go well right from the start on a large quilt. PRACTICE- until you are comfortable and happy with it....then quilt your quilt.