***** NOT A TEACHER *****
Good morning, Mr. Davis.
(1) I don't know whether the following is helpful, but I offer it for your consideration (in case you don't already know it).
(a) I didn't come to the party, because Tom was there. (I hate Tom. He was at the party. So I did not come.) (Comma gives us necessary pause)
(b) I didn't come to the party because Tom was there. (Everybody knows that I hate Tom. But that is NOT the reason I missed the party. I had a personal emergency.) (No comma because you need to say the whole sentence with a rising, uninterrupted tone in your voice)
(c) I don't read Newspaper X, because I don't like it. (No explanation needed)
(d) I don't read Newspaper X because I don't like it. (In fact, I love it. But it's too expensive for me. That's why I don't read it.)
Have a nice day!
Student or Learner