Anyway, I would love to meet any fellow BPers who work nearby for lunch, as I’m often just grabbing lunch and heading back to the office.

Given Airforce based nearby, assuming it is a good place for rental property. 

Look on Redfin yourself for recent nearby comps.

School already started so maybe transfer students.This is a little old school but what about hanging a flyer in a nearby gym.

They almost always are in locations with well over 100 year old properties, horrible school test scores, high crime, high vacancy rates, vandalism, strip outs, abandon homes and commercial properties nearby.

I've noticed on Trulia, Zillow, etc. that many properties similar to mine (I have a 4-unit, comps are mostly 3-units) have been increasing in value. If this trend continues would it be wise for me to order another ass...

Austin is a fickle market, but you can still find deals, especially if you are looking to expand into the nearby areas.I have taken the approach of Just Do It. 

For example I have a friend who bought 6 vacation condos at once on nearby okaloosa island around 2009.

Not far from Downtown, Freeway access is very close, Library nearby.

There are local forums here on BP where you might be able to find some nearby collaborators.