Offer adult toys as amenities. 

I personally require a recent picture of the animal so the tenant can't swap their toy poodle for a Pit Bull, current vet records, animal must be current on shots, etc. 

Hi Matt,Step one might be to get them a new baby gift or two---like a couple of little stuffed toys from Target or Walmart.Drop them at the door in a box like FedEx does with a nice little card of congratulations on the new baby.If that doesn't make YOUR life easier, then wait until the lease runs out.

you can look for BBQ grills, toys in the yard, cars in the drive way etc.   

Maybe a coloring book/crayons if they have kids, a chew toy if they have a dog, etc.  

Nothing crazy...a card accompanied by a bottle of wine, treats/toys for their pets, chocolates, the like.

Open up the floor registers and clean them out, this is not only good for your HVAC system, but also will reveal things like cigarette butts (unauthorized smoking), pet food (unauthorized pets), and the occasional kid toy (this is okay, since finding a barbie shoe or the missing lego will make a child happy.) 3.

My husband and I have toyed around with the idea of buying a commercial property but one thing we know for sure, people will always need a place to live so residential is our thing. 

Because the tenant was afraid a limb might fall on her toy dog.  

You can toy with the lease length too.In some of my properties we're going forward with soft increases because our tenant base has shown an ability to absorb it.