Potential Renters Don't Follow Through in Rental Process

[Winter Heintz]

Hello! I own a duplex, live in one side and rent out the other. I had the previous side rented WAY under value ($850 with utilities included) for the past 2 years. My previous tenants moved out and I currently have the property listed at $1,100/month utilities paid by the tenant (which is in-line with it's market value and worth). I have had so much interest in it it's hard to keep up. I have a thorough pre-screen process and ask questions prior to scheduling a tour. About 90% of the time after the showing the potential renters are interested and do the application and background check but when it comes time for the deposit to hold (I state the entire process and qualifications in the pre-screen and go over it with them in person so my expectations are clear), nobody follows through (non-refundable deposit to hold is half of security deposit at $550 and the rest of the security deposit ($550) is to be paid at lease signing). It is extremely frustrating and time consuming. 

My question is: How do I ensure these potential renters will follow through? Is there a way I need to be more direct with them in the process? I feel like they are all duds and say they can pay everything on time but then they don't, obviously I don't want renters that don't pay on time anyways but it just wastes so much time and money. Everyday my unit is not rented out it's costing me. Give me your advice!