OK then, you need to solicit feedback while doing the showings. Something is turning them off. While walking around listen to what they are saying. Ask them what they think of the place.
Look at your competition. Go on a tour of properties near where you are renting. See what they are offering and at what price. Take that and compare it to exactly what you have in your place.
Look at their price...are they charging more or less?
Look at the number of bedrooms/bathrooms offered. Is that what you are offering? This can have an effect. If this is a family area where everything is 3 bed/2 bath and you are offering a 2 bed/1 bath you may have a problem. You are too small for the customer base.
Look at finishes. Are the other properties offering granite and update appliances? If they are, and it's the same price as you, well, that tell you a lot.
Ultimately though, it will come down to price. If no one is biting at the price you are offering at, then that lets you know that they think it is not worth it.