good suggestions so far. I would add if you want to get good at free motion get a notebook or whiteboard and sketch. that gives you muscle memory. Patsy Thompson has information on her website and though she focuses on DSM the designs of course work well for longarm also.
https://www.youtube.com/user/CozyQuiltDesigns/videos. I also found the pajamaquilter dvd helpful when I first started
http://www.pajamaquilter.com/
Look at quilts or look at pantagraphs and try and sketch the design. repeat. you will get comfortable with your interpretation - like handwriting. then take that design to fabric. many designs spring off an initial one and Patsy Thompson is good at explaining that.
Have fun.