I guided out of South Florida and the Keys for over 15 years and made a good living at it. Had it not been for some physical problems I'd probably still be down there fishing.
IMO the most important things a guide can do for his/hers party is to educate and entertain. Have a good working knowledge of your local waters and quarry. If the fish eat, be able to explain why, if they don't, be able to also explain that. Get to know your clients, most people really appreciate that you take the time to find out a little about them and they're not just another pay check. Most of my good customers became close friends. Never, I repeat never, try to BS a customer. They're a hell of a lot smarter than they act. The people you want as return customers will understand that you can't limit out every day. Show some concern for the environment, if you see some trash that you can pick up and dispose of in the right place, do it. Not only does it make the area a better place to be, but it'll show that you really care about what you do for a living. I could go on and on, but you get the picture. Most of it's common sense.
I knew when my people were happy with my services when at the end of a day with no/few fish, they booked some more trips. Remember, it's a service business. If you don't provide the best service you can, you won't be in business a very long time.
If you've been guiding for any time at all, I don't have to tell you that it's one of the hardest jobs going. Just do it the best way you can.