Today's tip is probably another "Duh!" for more experienced sewers. I'm just starting to use my sewing machine on a regular basis, though, so bear with me.
There is little that's more annoying to me than running out of bobbin thread mid-seam. In my case, it tends to happen after dealing with a few other problems. Then finally I get a good rhythm going and the bobbin thread runs out.
My solution for this is to wind at least two full bobbins of the thread I'm using on a project. That way if it runs out, at least I won't have to completely shift gears to wind the bobbin again.
I know, simple, huh?