Time to head back to school!
May be different in Tx... but most schools I know of (here and east coast) require an MA or MS at the least to teach. Most require doctorates. No certifications needed, just grueling competition amongst other grad students and prospective professors. Even for "just" associate professorships, and if we're talking tenure track... that's cutthroat. Tenure track positions are starting to become unicorns.
Part of a Grad Student's aid package or degree requirements, though, almost always includes TA'ing (aka teaching). You get paid for it, just not very well.
In order to be a competitive candidate for a professor job, one needs the connections and the resume of having taught during their graduate work in every school I know of EXCEPT for in certain "guest lecturer" positions... but those tend to be rarely bestowed.
The above (needing to go back to school) may be good or bad news... but here's either the bad news or the worse news:
A lot of state schools are broke. There have been hiring freezes, salary cuts, and position cuts (even whole department cuts) nationwide.