To comma, or not to comma

One of the writing books I have recently finished reading had a great chapter on comma usage.

The author (an editor), stated the best rule in one sentence:

If the part of the sentence after the comma can stand alone, then it should stay. If not, then you don't need a comma.

For example: "The Sun rose in the morning but I wanted to stay in bed." You don't need a comma because "I wanted to stay in bed" can stand alone. "Bob ate bacon, and eggs" doesn't work because "and eggs" doesn't work. Great advice. Improved my writing immediately.