Gather proof that you've met Louisiana's residency requirements for divorce. You must live in the state on the date you file and have lived there for the year leading up to that date. Louisiana is a pure no-fault state. It doesn't recognize any fault grounds at all, so your spouse can't contest your divorce on the basis of the grounds you use. However, he can allege that you haven't met the residency requirement to file so you might need proof, especially if you recently moved into the state.
Determine what forms you'll need. Louisiana has three petitions for divorce: one for uncontested matters, one for contested divorces with children, and one for contested divorces without children. If you and your spouse own property, have debts and/or have children together, you'll also need an income-expense affidavit. Additionally, you'll need a child support worksheet if you have children. Louisiana has two types: one for parents who share custody and the other for parents who do not.
Download the forms you've determined you need. Some Louisiana parishes offer these divorce forms on their websites. You can also get them from an online legal document provider, but make sure they're specific to Louisiana.
Complete the forms and take them to the judicial district court in the parish where either you or your spouse lives. You'll need at least one additional copy. The clerk will accept your original documents for filing and stamp your copies as received. You'll need the copies for your own records and for service of process on your spouse.
Arrange to serve your spouse with a copy of your petition. If your divorce is contested, ask your parish sheriff to hand-deliver the papers to your spouse. The sheriff will file proof with the court when he's done so. You can also use a private process server, but you'll need permission from the court in Louisiana. If your divorce is amicable and uncontested, you can give the papers to your spouse yourself. Ask your spouse to sign a waiver of service, a form you can get from the court, and file the waiver just as you filed your petition.