Set a goal somewhat higher than you have achieved in the past and let people know that it is an ambitious, but achievable, goal. Their commitments will allow for similar commitments from others. Once that ball is rolling, the momentum will carry your campaign to a successful conclusion. At that point, invite everyone to participate in the campaign's success. Now is the time for your benefit concert, your bake sale, or whatever it is that gets everyone involved and becomes a celebration of the success of the campaign.
Annual campaigns can be fun.