things to know that come to mind: I lived in Waikiki on the corner of kuhio and seaside for a number of years.
1. parking in Waikiki is expensive. street parking is very difficult to find.
2. food is expensive whether in the grocery store or resturants.
3. 6 pack of beer costs the same as here.
4. for $2.50 'THE BUS' will take you anywhere on the island.
5.
TheBus - Routes & Timetables
6. Polynesian cultural center is Mormon owned consequently no caffeine or alcohol.
7. if you are leaving on an evening flight you should save pearl harbor for your last day. because check out time is in the morning and you will all day with nothing to do. and pearl is adjacent to the airport via bus nr 19 or 20. these schedules run all day long from Waikiki to airport and hickham.
8. remember as another poster said, don't take any plant life that hasn't been sealed and authorized. when you go through the screening checkpoint you will be checked for the usual stuff and without knowing it the "AG" folks will be checking your bags also!
sorry for rambling, these are just thoughts that came to mind that will be helpful to you.