Don't be too overambitious with the activities you choose, understand that you can't do everything. You should try to have a nice balance between relaxing and enjoying some of the activities that we have on the islands.
The best way to plan for Hawaii activities is to first make a list of all the things you want to do. Write down everything you can think of like snorkeling, golfing, deep sea fishing, hiking etc. Obviously you won't be able to do all these things, this is just a way to brainstorm everything that you can think of that you want to do. The next thing you want to do is make a list of the things that you must do for example: you know you want to go to a luau or Pearl Harbor. Once you have these two lists you can then narrowed down to a smaller list which incorporates both things you want to do and things that you might want.
Make sure that you pick age-appropriate activities. For example if you're older some of the Eco-tours may be a little too strenuous. Even a moderate hike will take all day in some cases so be careful not to choose something that would be too much for you to do. And likewise if you have youngsters make sure that they can actually do the activity that you're engaging in. For example, some snorkeling adventures and zip line activities have a minimum age requirement.
if you follow these simple rules and play correctly you'll have a great time in the beautiful Hawaiian Islands.