How do I get more reviews?
Ask at the dock, while the day is still fresh. Guests who had a good time are usually glad to, and almost none think of it unprompted.
The moment to ask is when they are holding the fish and grinning, not three days later by email. Reviews only count if the trip is recorded as completed on the site, so make sure bookings actually run through here.
The option to review appears on the guest's booking once the trip is marked completed, so keep that step up to date in your workspace — a trip that is never marked completed can never be reviewed. Then ask, at the dock, once. A message the next day with a line like 'if you enjoyed it, a review on the site helps us a great deal' works for the guests who meant to and forgot.
Do not offer anything in return for a review, and do not write them for guests. Both get a listing removed.