So I know SOUNDS need to be in caps but what am I capitalizing, the noun or the verb?

1. The DOORBELL rings.
2. The doorbell RINGS.

Which is correct?

2.

No stupid questions here.  

I'd say the sound is what you're emphasizing, so RINGS.

I don't do this as a habit. If it really needed pointing out then I might. The doorbell is the object, the sound is what you're drawing attention to in this case, I presume.

You want to capitalize anything that requires attention.

If you're introducing an unnamed character, use MAN or WOMAN, or another variant. Same goes if it's the person's NAME being used for the first time.

Mentioning that a street is lined with CARS is another example. One of those cars may HONK at you if you walk in front of it.

It's pretty straight forward when you get used to it.

I've stopped using capitals on everything other than character names.

And, of course, don't overuse all caps or else you'll water down the experience. Whatever that may mean. Lol.

Thanks guys! Very helpful!