Online forms for tenants, income and expense tracking, auto add late fees (or other charges you may have), rent collection, integration with other applications, ability to store documents, etc.   

As a starting guide for markets, here's an older BP blog that has some basic considerations:  https://www.biggerpockets.com/blog/2012/12/22/out-of-state-real-estate-investing/I'd also highly suggest David Greene's book on Long-Distance Real Estate Investing: https://www.biggerpockets.com/store

For example to become a licensed broker where I operate (Ohio) you need to go through government background checks, have worked in real estate as a sales agent under another broker for at least 2 years, have a college degree, have a physical store front with office hours, have done at least 40 transactions and much more that I can't think of off the top of my head right now.

Trisodium Phosphate (TSP) that you buy at the big box stores will work.

It's not in a bad spot... close to a grocery store in the back of a suburb a little ways away from a clean river, fairly scenic area. 

I found out he was bringing in big black bags filled with garbage every night when he’d come home and storing them in his room.

Just a few blocks West of the 405 and one block North of  the 10 freeways and inside the new Metro-Rail 1/2 mile radius of the special incentive development rules to encourage more units for housing that allow new construction to have "special" or "liberal" allowances of set-backs, more height up to 5 stores where 4 were the max just prior. 

There is a great place just as you enter Cedar Park that has great quality stuff and does price matching with all the big box stores. 

Store credit cards (JCP, Home Depot, ect) are usually the worst cards to have because of the lower credit line you are usually always using more then 50% of it.

Instead of having the Contractors go to the store whenever they are in need of something, they will notify the Lead who will record it.