Lots of great suggestions here! One other thing...
Make sure when your thread breaks to clip the thread up by the spool & then pull the thread from the needle down to remove the cut thread. That will help pull out any little fuzzies in the thread run. I got a tiny grey fuzzy caught in my thread run the other day & the thread snapped. Sure enough, when I pulled the cut thread down, the fuzzy came out. I rethreaded my machine & was good to go. You might even try doing that a couple of times before you start up again. It will clean any tiny fuzzies or bits of thread out to ensure it travels smoothly to your needle.