End of January, you should be getting 1099-K forms from vacation rental sites. Airbnb and VRBO send Form 1099–K if you earn over $20,000 and have at least 200 or more reservations in the previous year. If you used payment processors such as Square, Stripe, Paypal and had $20,000 and at least 200 transactions, they will also send you 1099-K forms. Tripadvisor/Flipkey sent me 1099-MISC form. It is important that you report your income correctly, hence the income should be equal to or more than the sum of these forms as they also file them to IRS.
You may see more $ on these forms than you were paid. Some OTAs include the gross payment they collected from the guests, but they keep some of them for them. In such case, you should report that difference as expense.