@Jordan Deaver
First, you need to set up your requirements for the property.
Here is what I use, verifiable income of $5,550 per month (3 times rent), good reference for previous housing history, pass credit check over 650, no outstanding past due obligations, no recent (10 years) bankruptcies, a clean criminal record, and no previous evictions.
Yours can be different based on the property and what the property will attract. Once you set your requirements, use these to drive your search. Also, once you get an app, call to verify the information on the app. Do not assume they will be truthful. I always verify job and previous housing info.
The other advice is to meet the clients and walk them through the property. I use this time to get to know the people and get a feel for them.
In the long run, you should develop a process that is the same for all prospects. You get a prospect and run them through your process. Don't skip steps, even for referrals or friends.