Think about where you will eat lunch and other details. Investigate that which your students will be investigating. This will help with Step Four. For a trip to the tide pools, be sure to find out when there will be a low tide. Recruit parents or other adults to be guides.
Students work much better if they are in smaller groups.
Send a letter home asking for volunteers at least two weeks in advance. Attach it to your permission slip and require it to be turned in at least a week prior to the trip. Phone the volunteers to confirm in advance. More adults will give you, the teacher, more flexibility, allowing you to move from group to group. Bring a camera to record the event.