Recruit a Benefit Committee that will be responsible for selling tickets. Get very specific commitments from committee members about the number of tickets they will buy or sell. Make sure the number is realistic. If someone is overwhelmed by what you're asking them to do, they might not do anything at all. Spread out the work, and make sure the total number of tickets your Benefit Committee pledges to buy or sell meets your goal.
Someone needs to coordinate the ticket sales.
The coordinator should call members of the Benefit Committee once or twice a week until the day of the event to see if they're reaching their goal. These report calls can be a gentle reminder, and should always be an opportunity for encouragement and thanks. Not only will a large part of sales revenue be eaten up by the cost of the goods you are selling, but precious volunteer hours may be diverted from more lucrative fundraising activities such as personal appeals. If the answer is yes, abandon the sales project. If you do decide to launch a sales campaign, choose a project with low or no upfront costs.