The best way to start is to go to the relevant TxDPS webpage, which you will find at http://www.txdps.state.tx.us/DriverLicense/OccupationalLicense.htm.
The part that would actually seem to usually require an attorney is the court order authorizing DPS to issue you an occupational license. The TxDPS website says that "Requests for an occupational license must be made to the county or district court where the individual lives or to the court of original jurisdiction where the offense occurred."
While I don't know your full situation, and you shouldn't rely on this, I believe Johnson County Court may be the best place. They may have resources available to help you complete a petition. If not, you could try and modify what Collin County has available, which you can find here: http://www.collincountytx.gov/law_library/forms/OccupationalDL.pdf.
Keep in mind, it's usually best to hire an attorney. If you think an attorney is expensive, not having one can cost you even more. Best of luck to you!
I am not your attorney. This is not legal advice. Do not rely on my statements for any purpose whatsoever. I may not even be *an* attorney in your state. Go hire an attorney.