• I don't care if your lease is 20 pages long: PUT IT IN WRITING! Sit down with potential signers (before finalizing) & read over the whole thing with them. Any infractions will be addressed, up to & including eviction. Be fair, but be firm.
• SCREEN, screen, screen! Better to go another month vacant than take the first warm body with a job: you may be verrrrry sorry!
• RENT IS DUE ON THE FIRST. Period. Eviction will commence as soon as legally allowed following non-payment. Period. This alone takes care of all kinds of excuses, sob stories, tall tales & BS. States are different, but know your local procedures & rights. Follow them!
• Don't handle cash. I know some LLs do, but I have a bank account set up for tenants to deposit whatever form of payment they want. I check each property account online the morning of the second. (See above if not deposited.) I won't touch cash; it's too easy to start "he said, she said" & have no paper trail to back it up.
• Respond, repair, replace - but on your schedule. Unless it's a true emergency (see first bullet), & you take care of the problem in a timely manner, tenants aren't going to turn into pumpkins if the faucet leaks another day.
• Get set up with reputable local contractors/tradesmen. Pay them on time, don't pester them for little stuff you could take care of, be polite, never think you know more than they do (if they're pros, you don't!), & don't hesitate to recommend them. A good plumber, electrician, HVAC tech, realtor, etc. is GOLD. Treat them that way.
• Document everything. (Especially nice if you get called into court.) That includes texts, receipts, e-mails, photos, daily work log, etc.
Plus everything previously said! Nothing like horror stories to make a point - learn from other's experience!