As I know someone who's organising a convention right now, I can tell you it takes a lot of work to properly organise one, and you're just barely scraping the tip of the ice berg.
First and foremost, plan ahead by at least a year. You'll be grateful. Before you get started, here are some things to consider:
* Location
* Budget
* Expected turnout
* Dealers
* Events, like contests
* Admission and pricing of exclusive items
* Advertising
First the Location. Let me tell you this: that'll be the one of the hardest aspects to deal with. Not only do you have to find a suitable one, taking all factors into account, but the rental prices can vary considerably. Be sure not to be satisfied with just one possibility, but spread your chances. It's like picking a university or college.
The Budget is just as important. The location will take the biggest chunk out of it, so be sure to leave some for making souvenirs to sell off.
Do your research properly, do you know how many collectors there are in Texas, or even in neighbouring states? Possibly the biggest reason people come to a convention is for the Dealers (mine is, anyway

), so look into that as well. I'm ashamed to say, I don't know any Texas-based store that sells Transformers, so can't help you there.
It can't be all Dealers, it has to be fun too, so organise some events or contests as well. Customs and Art contests are always good ideas, but the more unique the contest is, the better

Don't forget the prizes though!
Advertising will be hard, as a website for instance takes time to be put up. Again, it won't be free

Just don't raise hopes and expectations. Play small, but think big.
If you need examples of how a convention should look like, look into Dairycon and Cyb-Con, or in the BotCon archives.
The resident Rewind... well, half of one

- Jelze Bunnycat =:3
Looking for:
- TR Furos (Hardhead's head) and Crashbash (lost him

)
- PotP Punch head
- TR Galvatron right arm (the gun one)
- CW Brake-Neck/UW Wildrider, CW Offroad
- TR Twinferno & Grotusque
- Greenlight, Lancer and PotP Elita-1
- Legacy Core Slug, Sludge & Snarl