I have just had my long arm since the beginning of Feb so I'm still learning. I picked up on it pretty easily probably because I quilted on my regular machine before buying one. Backtracking gets better and easier with practice, and practice is the key to the whole thing when it comes to LA quilting.
Tension if the hardest thing that I've had to deal with the the LA. It changes depending on the thread or even the batting you use.
I always leave the stitch regulator on.
After you get the machine you will find you need other things, templates, rulers, pantos....the thread is really expensive! My machine works best with King Tut and it is $30 for a large cone.
Good Luck!