Get your Burning Man tickets immediately, as soon as you make a decision to attend! You can purchase them directly at the Burning Man website, where they begin selling out months before the festival (see Resources below).
Plan on spending as much time as you can at the festival, because once it is over you won't experience anything like it for another year. Ticket prices are the same whether you spend all 8 days or leave after 8 minutes, and the same goes for the expense of traveling to and from the festival.
Check out other possibilities to get a ticket if the Burning Man website has sold out. This could involve purchasing tickets to the Green Tortoise Shuttle Service, which sells festival tickets to its shuttle customers, or searching for a commercial ticket agency that stockpiles tickets for resale.
Make sure you and Burning Man are a good fit before you buy tickets. You will spend up to 8 days in an environment like nothing you have experienced, and invest serious time and money on travel and tickets, so it makes sense to spend some time making sure you know what you are getting into. Go to the The Burning Man Project--Welcome Home homepage and pay special attention to must-read items by clicking on "First Timers Guide" and "Preparation" (see Resources below).
Talk to real people who have experienced Burning Man personally. If you don't know anyone with this qualification, make connections by clicking on the "Regionals Network" link on The Burning Man homepage and following the links to find a Regional Group or Contact in your area.
Then attend the next meet-and-greet or other event, or use email or the phone to initiate personal contact.