I rented out my home before and I developed a variety of ideas that helped me greatly. Not all of these ideas will apply in your situation, so use what you can and disregard the rest. The first practice I recommend is to carefully screen potential tenants by probing for lifestyle and financial tells.
1) Don't trust everything they tell you. Words are cheap. Renters will say anything to get a good deal or to back out too.
2) Analyze applicants based on their: a) finances, b) lifestyle, c) personality, d) timing.
2a) Get two years worth of finances, savings, checking and on top of that run credit reports (they can do their own if it is current within a week). If they ever were evicted, pass. If they don't have enough in savings for six months, pass. If they aren't employed at same company for one year, looked at liquid assets. You can learn fairly quickly who is a saver versus a spender. I've never allowed a co-signer but always required a first and last months rent plus full security deposit upfront before any keys are exchanged.
2b) Are they a homebody or do they travel a lot? Are they handy? Are they healthy? Cook a lot? Active? Runner? Biker? Gamer? Single? Pet lover? Military background? Do they clean up after themselves?
I find the quickest way to learn a potential renters genuine lifestyle is determine how they spend their TIME. I Workaholics are rarely home that is good. So ask the applicants to describe their lifestyle and especially their weekends.
2c) To learn more about their personality ask probing questions leading with why are moving now. Also make sure to ask about their previous roommates/neighbors, living conditions, work or anything where they can "dish/complain" about their past. Notice the hidden forms of communication. Observe their body language and especially their tone; you will discover how they genuinely feel about various topics. If they have no problems complaining or badmouthing others, rest assured if anything happens, they are far more likely to reveal a difficult, whiny complaining pants personality. Worst case ask yourself the following, do you want to experience a landlord/tenant dispute with someone like this? Is there a higher or lower chance they might become vindictive if they feel they were wronged and are entitled?
2d) Timing, make sure it is not a month-to-month, at least one year with a rental clause that you the landlord can evict them if they violate the terms of the rental agreement. It takes time to fix a place up and make it presentable to new renters. This is particularly true if you furnish the room. Any unoccupied room(s) is lost income that you will have to cover. So while you may not feel comfortable renting out two out of a typical three bedroom single family home, I encourage you to think about why you want to rent to begin with. Odds are if you are looking to rent out a room it is to help offset costs, right? If this holds true for you, then dedicating more time to carefully screening out unqualified applicants will help save your headaches later on.
3) Get umbrella insurance to help protect yourself. Consider adding outward facing cameras on the property exteriors and blind spots. Last I checked, adding cameras can be a deduction, but confirm with your CPA if you are interested.
4) Require renters to purchase renters insurance. If they refuse, require a written and signed waver stating they will not hold you responsible for any loss or damages to their personal property.
5) Make sure they fully understand if they violate the rental agreement there will be penalties assessed. E.g. fail to pay the rent before the last day of the month a late fee of $50 will be added after the second day.
All of these steps greatly helped me reduce rental stress, set clear expectations and create a safer and happier rental environment for everyone.
Make sure to revisit this thread and let us know how things go for you. Good luck! Cheers!