Tenant pre viewing screening and filtering

Hi All,
Having chosen to market my flat on my own and not via agent, I want to filter time wasters and potential problem tenants. How strict and upfront are folks in my position, what measures do you take to ensure only quality tenants who can afford the place are considered and what benchmarks do you set or questions for tenant? Are you pleased with referencing service here from Open Rent? I have paid for Full Package but do not want to use 2x referencing options until I have done some upfront checks and filtering so any advice would be much appreciated.

Thank you

If you search the posts for screening questions etc you will find this question has been answered in depth in several posts