The best advice I ever got when I got my Juki LU-562 came from Dan. He told me to have it checked out by a professional, so that's what I did. They cleaned it, tuned it up, inspected everything for wear, adjusted the timing, and gave it a good lubrication for about $90 American. I dropped it off at the shop on Tuesday and picked it up that Friday. To me, it was more than money well spent.
Dan is also 100% correct when he says to throw away all of the thread that came with your machine and get some new thread - including pre-wound bobbin thread. I'm new to sewing as well, and I ignored that advice for about a month and just kept getting frustrated with thread breakage and tangles. I thought it was just the tension adjustments on my machine, but it turns out that wasn't the case. I picked up some #69 Nylon thread at the sewing machine repair shop and tried it out. Talk about the difference between night and day!
The thread, along with a new needle, made this old Juki of mine almost a real joy to use. Now all of my problems are with technique and not the machine itself. Practice is the only thing that'll fix that, and I'm still plugging away. I have so many pieces of scrap canvas, vinyl, and other materials that have been sewn together lying around my garage, it looks like an explosion at a quilting bee.
The secret is to use a new needle and new thread. Wind some bobbins from the same spool of thread you'll be using in the machine, adjust your upper and lower tensions while you sew on some scrap, then go for it. You really won't believe the difference it makes.
Keep practicing with it, and if you have any questions at all, you've come to the right place. Dan, ArmySniper, Horvath (Alan,) - heck, who am I kidding - all of the guys here are very friendly and extremely helpful. You couldn't find a better bunch of people IMHO.