There's already been a lot of good advice, and I can't add much except to say we lived in Houston for many years, and it's one of the biggest cities in the country. In population it is ranked 4th (last I looked - neck and neck with Philadelphia), but in area it's bigger even than that would suggest. It sprawls, and traffic can be a problem at any time. Even more important than show tickets are reservations at a hotel as close as possible to the George R Brown Convention Center. Use Google Map's "Search Nearby" feature to see what makes sense to you and book it soon as you can. Most reservations of that sort can be changed up to a day before, but check the policy of the specific hotel. Also, if you are driving a rental car, parking near the convention center can be difficult. There may be shuttle busses from some of the more distant parking lots, but a hotel within walking distance would be a big plus. I think there's at least one that has a covered walkway directly into the convention center, but I haven't been there in several years, and as a local, of course I didn't stay in a hotel.
One more bit of advice that applies to travellers anywhere in the world is try to acquaint yourself with the currency exchange rate and carry a calculator. Right now if you see a 10 USD price it's actually over 14 Australian dollars, and you will also be paying sales taxes which are not shown on price tags. It would be pretty easy for me in that situation to think I was looking at great bargains, when it might not necessarily be the case.
Wishing you a wonderful experience!