For instance, the sneaker industry re-trade market is huge and some re-sellers make upwards of $250K a year.

For example many properties in trendy areas like RiNo and Highlands are selling above ask to cash buyers (if there priced right to begin with) while buildings in less desirable areas will have less competition.

For example, the area around Lackland AFB is supposed to be solid with renters, and there seem to be livable houses in the $80-90k range - I haven't invested there, but I have been told it's good (although not trendy, so it isn't one of the "hot" neighborhoods - which could be a good or bad thing in my opinion, depending on how close we are to the top of the market).One thing I would say is to make sure to run your numbers realistically and conservatively, and be patient.

Would you rather have a 10% return on your money in a dilapidated war zone or in a trendy area that continues to improve?

North of Westheimer is Tanglewood and expensive & trendy. 

Personally, I don't look at any metrics to figure out the market trend. I

@Victoria Coleman population trend is towards moving south.

I see a lot of trendy areas popping up in affordable cities in the Midwest.

Trendy is nice if they can afford it and more profitable when times are good. 

I don't know if I believe those numbers, but the general trend is towards multi.