Having the property on your tax returns will help to wipe the mortgage expense with proposed rental income, making it easier to qualify for your next primary residence purchase.

To be as fair as possible, I'll let everyone know who would have qualified that the unit has been filled and is no longer available.

What new apartments are permitted around it...or 1/2 way thru construction, but not on the market.How do you become an expert or master it.....probably like any other skill...practice. 

It sounds like your question is what is the conventional guideline on using these rents to qualify ?

So many "investors" bury themselves in complex, expensive situations to protect themselves from some unknown threat to their non-existent business.Figure out if you have any shooting skills (or even enjoy the game) before spending money on $600 Nikes or an indoor basketball court. 

Strive for constant improvement, adapt to market changes, and continuously learn and develop your skills.

Personally, I'm waiting for the lawsuit by a seller against his own broker for refusing to vet a potential buyer and then show to a qualified buyer.

It was on the market for a long time because it didn't qualify for conventional financing will it being unlivable. 

But if you feel like you can learn the same skills on your own through experience and other resources, saving that extra tuition for your first investment might be the better move.

Call around and see if you and the property will qualify.