1. I use a lighter weight thread in the bobbin than what I use on top.
2. When I received my new LA (a couple of months ago), I made me a 'practice' quilt sandwich with a DARK sheet cut in half with my preferred batting. This enabled me to get familiar with my machine (loading, basting, etc) and... the dark color provided a great view of the stiches. You will be free to try a myriad of things w/o the risk of ruining a "real" quilt sandwich. Also, you can play and not have to worry about ripping out.
Have fun!!!