I track vacancy, employment rates, net migration, supply/demand, etc. 

Our stupid state actually employs people whose sole job is to try to trick landlords and realtors into saying something that they can claim is discriminatory.I don't know what state you're in, but I'd advise looking into your state and local regulations so you don't get ambushed.

Truth be told, I would not have been able to do it without my business partner who was previously self-employed and was available to staff the office 9-5.

I wish I could click a box that would require anyone wanting more info to complete the basic information that we want--income, employment, etcI have found that texting my response template gets a lot more responses than emailing.

We have employed this strategy ourselves several times and any time you can cash flow $2000 a month and possibly pay the place off in 6 - 7 years you have hit a home run.

Median income, population growth rate, key employers, etc. 

@Kurt DefenbaughIf you are self-employed with no full-time employees, you can open a solo 401k plan which would allow you to make a $55,000 tax deductible contributions for tax year 2018 as long as you adopt the plan by 12/31/2018.

In general, you look at the MSA population growth, job market growth, major employers, major industries present, whether the infrastructure exists in the area, is supply lower or higher than the demand. 

We just got a non qual loan (we are self employed low net income), against our home which we own with no mortgage.

Florida employment numbers continue to shine. https://www.sun-sentinel.com/business/fl-bz-unemployment-october-20181116-story,amp.html