Houston has a strong MLS, and Har.com is an excellent site.  

C21, Keller Wms which is strong on training and helping out.

She's all in on real estate.I'm slowly trying to put together a strong foundation to make the the jump into leaving my, all too-often monotonous, 8-5 job.

My understanding of the market there is that it is strong for the midwest: reasonable population growth, good jobs, solid neighborhoods, good cap rates, etc.Because I'm quite busy, I don't have the time (or willpower, to be honest) to hunt for deals myself, find contractors to renovate, and do all that work myself.

Learn from it and see what you can do to prevent it (a lot of that is strong policies...when they are 1 day late, BOOM, notices go out, start the process right then (at least notifications) the reason why is not to create a lot of paperwork for you and hassle, it is to train them that they can not "float" the rent to pay for other stuff, the better trained the renters are the less hassles you have, the better your return, the lower your time commitment.   

I’ve had a brand new “9 year” water heater go out in 10 months, and a “6 year” water heater still going strong after well over 10 years.

If you have a strong owner occupant pool for the area, it might be best to sell it vacant. 

I am trying to determine a strong market to start searching for deals but am not sure where to start.

Do your tenants plan to have WWE style fights at the duplex?

Strong area.