1. You do NOT want to make an s-election for an LLC that is going to hold an appreciating asset like real estate. If you do, and then you want to take the property out of the entity for any reason, it could be considered a taxable event.
2. You need to be certain that you keep the LLC assets separate from your personal assets. Don't use the LLC bank account to buy personal expenses like groceries, make car payments, make ATV payments, etc. (happens more often than you might think).
3. A good CPA is worth it!
4. Be prepared to get spammed with official looking correspondence that tells you to buy a Certificate of Existence (or similar doc, depending which state you live in) for an exorbitant fee. You likely don't need it and you can get it cheaper by yourself ($20 in Utah).
5. Don't register in WY or NV (both are en vogue) unless you live there. It's soooooo much more expensive in NV to renew each year. I also don't want to have someone sue me in Wyoming since I don't live there. Register the LLC where you live, or where the rentals are if they are in a different state from your residence.
6. There are other things as well to watch out for that make it a good decision to speak with an attorney.