The one thing I learned from chartering is that you are in the entertainment business, you have to do everything you can to make the trip as enjoyable as possible. I also learned that it's also the little things that guest notice. Everyone likes a clean organized boat. And if you have women onboard, the head absolutely has to be really clean and fully functional. If it smells down there, or the bowl looks like it hasn't been cleaned since the day it was installed, she probably isn't going to come back, I'm not even going to go into having plenty of toilet paper, and make sure you tell them how it works before leaving the dock. Have extra plates, cups, napkins and utensils in case they forget. Supply a clean cooler with plenty of ice as well. And don't let anyone "over indulge" (no drinking by the crew). Talk to the charter a day or two before to go over things, and ask if their is anything they might need for you to bring (like chairs). Your bread and butter is repeat business, and they will pass along recommendations. You will have to be firm on some things, but don't be a tyrant. Keep a list of your customers, and send them out updates now and then about open dates. Keep a list of the problem customers as well, let them know your all booked up!
Like any business, it has it's ups and downs. Keep a positive attitude and you'll figure it all out.
Good luck!!!