If it's a neighborhood of SFHs, maybe these issues are not applicable or less serious.  

I want to see how you verify an applicants payment history.https://docs.google.com/forms/...

You can also offer online application and lease signing processes, as well as online payment options, to make the rental experience more convenient for your tenants.

Or any specific questions you include on the application?

A broker's license requires that the applicant has been a realtor for 2 or more years and then it comes with increased education requirements.  

I had a young man with a very weak application that claimed a Trust fund of $50,000 but I wouldn't rent to him unless he paid the entire year in advance because he is more likely to spend that Trust money on a truck and then not be able to afford rent.

These are usually free or extremely cheap (less than $20 a month) and allow you to track properties and renters, market online, run application screening, collect online rent payments, and more. 

Additionally, get a signed release from the applicant so you can provide it to references, basically releasing them from liability about whatever they disclose to me. 

Currently I use a third party service where the applicant goes online with their own PC after they get home.

While there is so much advice from real estate investing at large which is applicable to this space, I hadn’t yet found a book primarily geared towards the small multi family arena.