You might visit IEC as they offer many courses for such test. I taught there for a number of years, teaching reviews for SBCCI, and City Of Houston master,journeyman,apprentice along with the continuing ed for Lic renewals. I am not sure about the Texas State test format but would think it is similar to SBCCI format. I like Mike's design and presentation, but Tom Henry was a close match to the SBCCI. I took San Antonio but it was geared to SBCCI with a slight modification. The Houston exam was like no other and there was no way but through IEC or IBEW along with a couple of local authors that it was passible. I sat with fifty others, some PE and EE's and only 4 of us passed.
I also used some of stallcups study guides but his presentation gives me a headache. To much info in too samll of a space. The NEC handbook is a good tool as well.
Browns Book store carrys a ton of books
http://www.brownbookshop.com/SearchResult.aspx?CategoryID=1517
You might invest in a good test making software and load you own questions, when I took Houston I had a database of 2000 know questions. I practiced this everyday for months until I could memorize at leat 90% of the questions. I would say there were at least 30-40% i knew right off the batt. This helps you spend more time on the question you do not know and have to think about. The biggest key to passing test is study only the question they will ask. This will work except in some cases such as Houston where the question were made up the day before the exam, at least on the open book portion.
Good luck
Bill Giffen