Consider how often you will meet, the targeted age group, how you will communicate with members, and the locations you can use. Then invite people to join. You can invite neighbors, classmates, kids from karate, and extended family. Consider reaching out beyond your normal social circle to make new friends. Or don't. Even a family nature club with one parent and one child is a rewarding experience worth doing!
Plan a short lesson followed by an activity and then free play in nature. This can be in conjunction with a local event (e.g., beach clean up) or something you design. It can be as simple as talking about how picking up trash prevents animals from choking on it, picking up trash, and then playing for an hour. It can be as complex as inviting a guest speaker to talk about meadow fragility, repairing a boardwalk to protect a meadow, and then playing for an hour. Either way, the kids will love it.
Timing: For kids under seven, try to keep the lesson under ten minutes, the activity under 45 minutes, and the free play to an hour. Kids older than seven have much longer attention spans, but rather than extending the lesson, incorporate more lesson into the activity and ensure they still get lots of free play time at the end.
Safety: Make sure each child comes with a chaperone. Check planned area for hazards (e.g., poison oak). Check the weather forecast. Assemble a first aid kit.
Contact members and let them know the time, place, what to wear, and what to bring. List even the basics such as sturdy shoes, long pants, sun screen and sun hats, water, and food. Let them know if they will need additional equipment such as gloves. Let everyone know if there are hazards such as wasps' nests or poison oak.
Arrive early to scope out the area. When members arrive, greet them and have them get into a big circle. Have everyone introduce themselves by saying their name and their favorite animal. Then tell everyone the plan and give a short safety talk. Next, give a short lesson or invite someone else to give one. It should be fun and informative.
After that, get everyone started on an activity that helps the environment. When the activity is over, it is time for free play—unstructured play in nature.
Finally, close out. Gather everyone back into a circle and have each participant share one thing they observed in nature. Older kids may like some time to write in a nature journal. End with a toast, "To nature!"