To vote in Texas, you must be registered. Simply pick up a voter registration application, fill it out, and mail it at least 30 days before the election date. You're eligible if:
You are a United States citizen;
You are a resident of the county where you submit the application;
You are at least 18 years old on Election Day;
You are not a convicted felon (you may be eligible to vote if you have completed your sentence, probation, and parole); and
You have not been declared by a court exercising probate jurisdiction to be either totally mentally incapacitated or partially mentally incapacitated without the right to vote.