I also live here in SE Texas, near the coast ( and too close to Houston!).
The major thing you need to worry about is the 1/4" nipple that ties into your pressure switch. That will be the 1st thing to freeze. Wrap it up if nothing else.
Water comes out of the ground around ~60 deg F. Put a tarp around the tank and weight it down. The most important thing is to keep the wind off the tank/pipes. I have run a small drip before and it works great. As long as the pump kicks on every hour or two you'll be fine. I really don't expect it to get that cold here on the coast but up closer or above Houston it can get pretty cold.
FYI for all you yankees-we don't have basements here in Texas, and it rarely freezes here in SE Texas. It occassionally dips down to 29 deg or so, but rarely do we get down to the 20's for days on end. It's a good idea here to keep the tanks etc. outside because during the summer time they will sweat a lot and make any garage or shed damp and moist, not to mention what happens when you have a leak etc. We keep the pumps/tanks/pipes/wells outside because it makes it easier to work on them and maintain them. I have seen people go way overboard with the insulation and when it starts heating up in the summer we got a lot of calls and sure enough, too much insulation etc. burned up the motor.