I don't know about other areas in TX, but I keep a close eye on Austin-SAN corridor, and I'm familiar with the market in Kyle, New Braunfels and NE San Antonio.

If you have a lot of family in OK, that can be a great place to start assessing since you have dedicated boots on the ground, as well as a reason to visit.Don't overthink the analyzing of markets when you are still figuring things out.

I bought some commercial properties (5, 6, and 11 units) and they were all off-market and seller-financed.Learn how to make the numbers work for you and the seller.

Then to find inventory, you need to search out, i.e. network, and find out who is creating these type of notes or you help people that may have an interest in seller financing how to create a note that is marketable to the secondary market.

Study the market.

Go off the % allocated via the county assessor's determination of market value?

There's a tenant that's month to month, rent is at least $800 below market rent, so I told the seller I need that unit to be vacant.

The only two ways to rectify this are (1) purchase the property far below market price or (2) significantly increase the property net income usually through some method of “repositioning”. 

One strategy is to pursue properties (in your preferred markets) that have been listed for sale for over 90 days (even longer is better).