What I may do differently is more research about which blocks in the 40 block low income area are more stable than others and concentrate there, or after every 5 doors buy one non-low income property to improve the mix and sanity level.  

Over concentration of a particular asset type in the portfolio is another type we will discount and bulk sell.

Mortgages aren't the Titans of Detroit that cars once were, and I have no personal material or financial interest in Detroit aside from (obviously) lots of telephone-only colleagues there, but it is one area I will be watching for a "repeat" of what can  happen when too much business in a metro area is concentrated in a single industry. 

-I love the advice of concentrating on a younger associate.

Multi-family over 4 units get to be a different thing as you have a higher concentration of tenants and the public on premises. 

In Las Vegas, for example, there are three major tenant segments: one with an average stay of less than one year, another with an average stay of over five years, and a third with an average stay of less than two years.How do you find a segment with a high concentration of people who stay many years?

I am concentrating on multifamily partnerships with cashflow within the first year and forced appreciation potential.

Concentrate on reducing your risk by getting as educated as possible before making a move.

I was into REI & stocks, but abandoned the equities after the infamous Black Monday (1987), so I concentrated on just accumulating Real Estate.

Here is some of my thoughts: You may need cash flow to pay the bills, but if you do not you should be concentrating on total return.