I recommend reading the chapter 17: Managing Your Rentals (Part 1) from the book "The Book on Rental Property Investing: How to Create Wealth with Intelligent Buy and Hold Real Estate Investing" by Brandon Turner. He explains really well about how to find and screen applicants for your rentals, rental agreements, and how to deal with common tenant issues (like not paying rent). Chapter 18 (Part 2) is good to read as well.