I have two daughters who love being on the boat ages 7 and 8. Like was said before let them do different things like pick out lures, have input on depth with selected options, steer the boat, lots of snacks, play games like who can kill the most flies to help feed the bait fish, music for them to do a lucky fish dance to or make up a new one if that one does not work, show them how to net a fish, fight a fish, have them look through binoculars to see what other people are doing (only if they don't get sea sick), etc...
The main thing is make it fun and interactive. I have and still do draw on these a lot. When the fish are cooperating there is no boredom and then each fish provides high energy and buys time for the next fish to hit. The other thing that I found was to start short if the fish are not in the mood and try again another time with them. Just some suggestions from a dad of two active girls. They are my best two fishinig buddies now and are always ready to go out.
Hope this helps.
Best of luck.
Phil
Family Style Fsihing Charters
http://www.familystylefishingcharters.com
This is my oldest with her biggest solo salmon from last year - this year she already beat it with a 12lb 13oz brown.