I used the materials found on the TEA website (sample TAKS, TExES Study Guide, and Sample TExES Test) to determine what areas to study. I used Khan Academy (which was sometimes more in depth than necessary), physicsclassroom.com (probably the best resource I found), and the "crash course" YouTube channel (very helpful for Chemistry, Biology, and Ecology overviews) to get detailed informoation on specific topics. I took practice tests, wrote down topics that I didn't fully know, and searched online for explanations. YouTube and Google are excellent resources for tutorials. The most difficult aspect of studying was determining how in depth to go on each subject. I studied for about a month and went as in depth as I could. Some of the information was unnecessary, however allowed me to make a more informed decision on questions I was unsure about. So, if you encounter a word or concept that you don't know, at least glance at the Wikipedia page to get a general idea of its context.
I passed and did slightly better than I expected. I wouldn't say the test was particularly easy or difficult. It expects understanding at a higher level than 8th grade, but I would not say it was college level material. The majority of the questions were reasonably easy, but only because I understood the question/answers and could rule things out. The more difficult questions involved very specific knowledge of the topic or had several answers that both seemed reasonable; there were not as many of these as I expected. I struggled with some of the calculation questions involving Physics and Moles in chemical reactions, so I would recommend really focusing on those. There were also a number of questions related to teaching practice, which were slightly difficult because I haven't had any training on types of assessments. But, most of these just required some common sense. Other reviewers have noted specific areas to study and those are accurate, so check other responses as well. Definitely understand types of rocks (including specific forms: ie basalt, granite, etc.), know the periodic table (groups and reactions between them, the components of the atom, and radioactive decay), know trophic levels and taxonomy, makeup of the atmosphere, biosphere, layers of earth, tectonic plate movement, the water cycle, photosynthesis, cellular structure/organelle functions (including ATP creation), understand the nervous system and the endocrine system, and astronomy (life cycle and types of stars, composition of the planets, and how galaxies are dispersed and clustered). In terms of Physics, make sure you can do basic work/force calculations, understand electricity/magnetism, and the properties of wave s (sound, light, electromagnetic). I know that's a lot, but I wanted to include as many specific topics as I could recall. Finally, mark any questions you are unsure about, move on, and come back at the end. I would also recommend going through each question at the end to make sure you didn't miss something. You have plenty of time, and I caught a few questions where I had overlooked some minor detail of the question. Best of luck.