I'd just knock on the neighbor's door.

Hi Richard,Not a knock on you but I hear "I am very ambitious" from young people at least 2x a week. 

I can knock on the tenant's door but what do I say?

My personal thought is that door knocking will be the most successful.

A very cheap and effective method for finding deals is door knocking.

I was in sales and out knocking on doors.

Expenses seem high and if there is a way to meter water and make tenants pay (and check if that is norm in the area) or knock out some of these larger expenses, numbers work much better. 

I'm about a month away from finishing my BRRRRR property, and unfortunately the basement windows were all knocked in, and so twice thieves have been able to kick in the boards and break in and steal from me and my contractor.

Water/bleach solution works well but is more labor intensive, pressure washing is faster but you have to be careful that you don't do it too often as it will knock the granules off the shingle, reducing the life of it.

Once you knocked out this wall you realized you had to rerun new plumbing and electrical... etc.