Celebrate, Party, and Enjoy!
You have to enjoy the success of every fundraiser. If there is a celebration, your team will enjoy fundraisers. There's something about a party that makes all of the work and struggle seem worthwhile. It doesn't have to be a big or lavish celebration. Infact, the celebration should match the scale of the activity. It would seem goofy to have a huge party to recognize the "spare change" jar you put out at the choir concert... but the next time the choir meets you must acknowledge how much money the "spare change" jar collected and thank the person who was responsible for it (thank them at the choir practice AND send the person a thank you note)
If you have a garage sale, throw a party. Order pizza! Recognize your volunteers (and send a thank you note). Something funny is going to happen at the sale, for example there will be at least one item for sale that either won't sell or you'll be shocked that it does - maybe it's the the floor lamp with the fuzzy lepord lampshade, did I mention it has fringe. Use this as your "trophy" if it sells, make a mock award that imortalizes that lamp! Something crazy - the more outrageous, the more fun and the better chance you'll get more help for the next fundraiser, and yes, there will be a next fundraiser so you will need these helpers!
Sometimes the celebration is a great time to ask the question "How can we do it better" - most of the time it's best to pull your leadership aside and have a wrap up meeting to conduct this.
If your fundraiser was a disaster - you still need to recognize those that helped, just be careful not to pour salt in the wound. A simple "thank you note" will do. Remember, at age 13 I was top seller for our dance studio candy sales and I was never recognized and quite frankly I felt used and didn't sign up the following fall for lessons. Egos can be bruised. Those reading that have a business like a dance studio better pay attention to my example because your business depends on having the students return! Remember your G-U-E-S-T acronym - the final item is - thank your guests!