The best thing to do when you first start is to just get a feel for the motion. Instead of working on a quilt, practice on some sample pieces. That way you can focus on the process and not the results.
Try stippling, meandering, follow some outlines, etc. Try to find the sweet spot between the speed of the machine and the speed whith which you move the fabric.
I can recommend the book "Machine QUilting Made Easy" by Maureen Noble. She has some good basic exercised.