Keep in mind that quality properties attract quality tenants. Right now, at the very least, make sure the unit is freshly painted in a neutral color and take the time (or spend the money) to do a deep cleaning.
If you have access to some funds, determine what improvements or upgrades you can do on the unit with your budget in mind, and how much more you can ask in rent with those improvements. If the extra bump in rent will pay back your investment over 3 years then that is money well spent.
For example, if your remodeling budget is $6000 and you are able to get a rent bump of $200 over a 3 year period you will recoup that investment.