Why is it that the more I focus on falling asleep, the harder it is to do so?

Your brain is active when you focus so that's why it's harder to fall asleep. Your brain can't let you sleep if it's too active

That is okay. A few things: (1) Something could be bothering every night, or has been bothering you. Write about it. Write about your feelings and thoughts thought for thought, word for word, and read it over. Read it, and see what is bothering you, and how you can make the situation better. (2) When you are not in the mood to write, do not make yourself sleep right then, and there. Get up, and walk around. Give yourself 5-10 minutes of walking around the room, and it should help.

I would feel like stressing too much about it and make it worse. You could use relaxing music or something that relaxes you like a hot bath or something...