There's a lot to do in Oahu, so you'll probably need more than a week to really know the island. Don't stay just in Waikiki as there's a lot to explore.

This thread on Trip Advisor forums has a lot of info on things to do in Oahu for a first time visitor. 

In it you will find a list and a map with:

  • Activities
  • Attractions
  • Beaches
  • Luau's
  • Suggested itineraries
  • Some restaurants

Print the list and follow the suggestions with the map.