1) COMPARE your place to others like it in the area on Trulia, Hotpads, Homes, etc
2) Look around your area by driving and seeing if there are any "For Rent" signs. Call the number, usually the owner, and ask how much they're renting the place they are renting for
3) Be REALISTIC about the condition and how your place actually compares. Take into consideration if it's on a busy street, what type of homes, or business is around the home you're renting.