I'd focus on getting a better property manager, their job is to shield you from most of these headaches and to prevent them in the first place through tenant selection and doing regular property inspections.

Begin small by making regular contributions to build your portfolio over time.

For clients you bill regularly, you can schedule invoices to send automatically, so you don’t have to do it manually every time.

Things change regularly and I would truly be interested in hearing from investors "everywhere". 

If after adding the additional monthly recurring costs (electricity, gas, water, internet, insurance, lawn care, snow plowing, etc.) to the standard long-term costs (Mortgage, taxes, regular insurance, etc.) the property won't net at least $100 if I can get the average rent I see on FF for that area, then the property isn't worth more investigation.

Instead, just make it a habit to show up regularly and deliver amazing content.

We’ve had great success with our listings, regularly achieving 5x the market average ADR on Airbnb and receiving frequent offers from local realtors to purchase.We’re now considering scaling up with a new project and have been approached by a friend who’s interested in partnering with us, providing financing for renovations.

If you have been using expensive vendors, consider switching to more affordable service providers or negotiating bulk discounts for regular services like landscaping or repairs.

Liens are being filed regularly against Blacktip-involved properties.

If 80% of $4,200 ended up on the depreciation line (in addition to the regular depreciation of the building) - you are fine.