It's kind of an art form, if you think about it, that is cultivated from experiences both good and bad.

Not full of heretowiths and where-for-art-thous lol.

I told them that they can't paint, but they can put up lots of big colorful art, as long as they patch any holes when they move out, basically.  

The art (which I'm learning more about every day) is in correctly forecasting both of those metrics.

. :-)"The Art of Saying No to Tenants" by Sue Kelly. 

Just wondering, is their an art to doing this, should I be getting them to fill out certain information before I show it to them, should I be screening them over the phone before agreeing to show the apartments?

Art, needs to be brought current. 

I'm guessing the art of claiming damages were caused by a break-in (instead of by their own doing) is common practice. 

She gets upset and tells me she will have to do the cleaning next week when she is off . " No , your lease is up today , You will have to wait the legal 45 days for your deposit , AND i see you painted some walls , someones crayon art work is all over the door , all the screens are missing , the grass wasnt cut , you wont be getting the full deposit back "   She then tells me that she will get most of it back , 2 gallons of paint is $50 , cutting the grass is 30 . and the screens arent her problem .

Landlording is an art. :-)