Get a mirror that is on an extension like a radio antenna. I got mine at O'Reilly Automotive. I quilt about half a row and then take a flashlight and my mirror to check my stitches underneath. At the automotive store I also got a strong magnet on an extension for picking up pins and needles from the floor and a magnatized parts dish to hold my pins. These items were quite a bit cheaper than ordering them from a quilting site.
For practicing on the longarm, I got a wide piece of muslin and made my "sandwich" from that. I drew straight lines on the muslin and practiced "writing" the alphabet in cursive. To keep from getting bored with that I would also "write" words and sentences. This is a good way to help you get comfortable with the machine and perfect the curves and lines.