What are the impacts of your interpretation?
It’s a good idea to take time to think about the potential impacts of you interpretation, not just on the visitor, but on other factors, like the site itself, or if in a place where people live, the local population. In the latter case hopefully they will be involved from the start.
The impact of signs and panels on the site is often overlooked. If your using permenant interpretation, then think carefully of the visual impact and the siting of the interpretation. If it detracts form the site and therefore the experience, you may need to re-think.
The Severn Estuary is a internationally important site for overwintering birds, so care needs to be taken to ensure that any activity, including the activities of visitors, does not impact on the things which make the site so special.