You'd be wise to consult an attorney who has experience preparing these petitions but if you want to do it yourself here's what I found.
I haven't found anything specific for LA but I found a couple of articles about the process from other states that might be instructive:
I also found two sample petitions that should give you an idea of how to set up the format showing your local criminal court information. One is a federal court form and the other from Texas. Both are in a pretty standard format for court papers.
In the body of the petition you basically put in everything positive that you've accomplished in the past year and a half and attach letters of recommendation.
When you file your petition with the court, you send a copy to your PO (and keep one for you). Make sure you complete the affidavit of service at the bottom.