I started writing one version of my college essay, but I’m afraid that I’m going off topic or not hitting the mark. What questions should I aim to answer in my essay that adcoms are looking for?
There is no “right” answer. You write an essay that adds to the overall picture you are painting of yourself as a potential student at your college: your stats frame the picture, your LoRs and ECs sketch the outlines and your essay(s) add the color. The more you know about what the school(s) who will read the essay are looking for the better, but at the end of the day the topic is you and the mark is ‘this student looks like a great fit for us’.
Pretty sure that won’t feel like a helpful answer, but it is a true one. Good luck 
typo correction: …as a potential student at {i]their college
They want to read it and say, “Yeah, he gets us, what matters to us, and he’ll fit right in here. He’s the sort of kid we look for.”
They do that mostly via the attributes you show. (Show, not just tell.) That tells them a lot about your thinking. What you show needs to be relevant to what they seek. Eg, it may be super important in rounding you out to write about your dog, how you love to take care of him, runnng with him frees your mind…but there are no bullets in admission called “loves pets.”
So, try to learn what traits your targets do want to find.
Also, it’s not so much about the prompt topic but rather how / why that topic is important to you, what you plan on doing about it, etc. D started writing essays today and wrote a great one about X. Problem was it was more of an opinion piece than really showing why it mattered, what she was planning on doing about it, how it affects her and people around her, etc. In other words, it wasn’t about her and handling the topic, but rather just about the topic. Anyone could have written that. Make it personal and only you can write it.
Be memorable!
I think that if you write an essay that makes the admissions officer think “I’d really like this person as a roommate or classmate” that’s what you are after. What makes you interesting? How can you show your intellectual vitality?