You should be able to download a standard application form from fair trading NSW. This coveres the questions you can ask the tenant when they apply for the property. Perhaps the question you should ask is what questions to ask their references?
Always ask their current landlord / agent how their routines were, how were they to deal with, how did they pay their rent? Was it regular payments which were easy to follow or did they pay in fits and starts never quite sure of where they were up to? Did they have any pets that they were aware of (even if it is on the appliation, sometimes they put down 1 dog when they have 2). What is their reason for leaving the house? Have they been sent a notice to vacate if so why? Would the landlord have put off sending this notice if the tenants were better??
With their employment always call the last few references provided. Find out why they left their last job (were they fired or did they choose to move on), how long have they been at the new job, are they reliable, punctual and well presented? Is their workspace kept clean? Has their boss met the rest of the family? If so, would they be willing to rent an investment property they owned to their employee? How much are they currently earning. Is this a base wage plus bonus or bonus included?
As everyone else has said, you will never find a perfect tenant as the perfect tenant is different for every landlord but you can certainly find some very good ones.