The document outlines 3 major mistakes landlords make when renting their properties and provides tips to avoid them. The mistakes are: 1) Failing to properly market their properties online where 90% of people search for rentals. 2) Not setting rental rates appropriately based on market research and ensuring tenants can afford the rate. 3) Being too lenient with tenants and not maintaining appropriate landlord-tenant boundaries which can lead to issues collecting rent and maintaining the property. The document provides strategies in online marketing, setting rental rates, screening tenants, and establishing clear expectations as a landlord.