Start planning your ‘thank yous’ long before your event is finished.
Create an ongoing database of businesses and individuals who contribute to or sponsor the event, including the name and contact details of the person you communicated with, and their role in the event (or what they donated).
This list should include all your volunteers and workers (including teachers) as well as individuals and businesses who provide prizes or sponsorship money.
Make Certificates of Appreciation with the name of the person or business and the details of your school/club event and date. Depending on your budget, present the certificates in neat frames, printed on heavy card, or laminate them.
Nominate one person to be responsible for updating the database and creating the certificates, and make sure the database is finalised shortly after the conclusion of the event. It will then become a useful ongoing tool for future events, and subsequent organisers will have an idea of what support they can expect from the community and where to start when looking for donations.