Expect the unexpected! Beyond the easily visible and predictable flooring/repainting/cleaning/landscaping costs, figure that you will have more than one discovery of other important issues - the water heater needs to be replaced, the garbage disposal seizes up, the rain gutters are broken, some internal wiring is messed up and a light doesn't work, a bathroom fan starts making lots of noise after its run for a few minutes, a water main breaks..
Make sure you have a cash cushion - or line of credit (credit card in a pinch) which you can use to address unexpected costs, some of which can be pricey.
Once you get a renter in place and start operating, consider all your routine costs - property taxes, insurance, local licenses and fees, maintenance and gardening, utilities and city services (that the tenant doesn't cover), tax preparation, legal, landlord association dues.. and put extra aside for non routine repairs and capital expenses.