Weather a class clown or a nerd, school offers a variety of subjects to study. If you are a graphic designer, chances are you are a visual learner. Many non-profit educational organizations are in need of affordable designs to appeal to children and visual learners alike. You have the ability to affect the up and coming generation with design, so why not pick a subject you are passionate about and design a poster?
Don't have a particular passion or don't know how to start? When facing broad possibilities, remember that you want your poster to be unique, so it may be smart to avoid over used topics such as the water cycle. Basically every Environmental Science book has a diagram of the water cycle, so choosing a different topic could be more beneficial to a client (or potential client). If there is a subject that interests you such as Environmental Science, then take a look at some non-profit websites—see if there is a potential need. Even if an educational poster is unsolicited, you can send a proposal of your design explaining that you are very excited about the organization's mission and that you want to give support through your design abilities. Better yet, if there is an organization that you strongly support already, contact them offering design services and ask if there is a specific need.
When creating an educational poster, remember that illustration and photography has a strong impact on memory—especially in younger audiences. Types of posters that work well in the classroom generally depict a process or give some sort of instruction. Because of their nature, educational posters should have distinct hierarchy, direction, and organization as well as language appropriate for your particular audience (obviously vocabulary will differ between elementary and high school students). Also imagery and artistic style may speak stronger to certain genders and age. For example, Delaram Rosami's photographic poster for Iranian women's rights would be more appropriate for older children in comparison to Nicte De Anda's illustrations for the Houston Zoo. View slideshow for reference.
Another good tip is to remember negative space as too much going on in the design can overwhelm or distract the reader from the message.