Travelling to Hawaii in November, spending three days on Oahu and seven days on Maui. We have been to Oahu twice before and done most of the normal touristy things like Diamond Head, Pearl Harbor, car trip around the island, would appreciate any other suggestions for things to do. Staying at Pacific Monarch hotel.

Have been to Maui once before, and have done the Road to Hana, sunset on Haleakala, etc. Staying just outside of Laihaina. Again any ideas of places to go, things to do would be appreciated.

Here are things I've enjoyed on Oahu when staying in Waikiki without a car. With only 3 days you won't have time for all of them! But some ideas...
Iolani Palace
Foster Botanical Garden
ShangriLa Estate tour
Honolulu Museum of Art
KCC Farmers Market (Sat AM)
Hyatt Regency Farmers Market (Mon/Wed 4-8pm)
Royal Hawaiian Band
Fort deRussy Park
Kapiolani Park
performances & classes Hawaiian music and dance at Royal Hawaiian Center (free)
Kuhio Beach hula mound evening show

Thanks Suze. I had read some of your suggestions on Trip Advisor, appreciate your advice. We are in Oahu from Tuesday night to Friday morning so will miss the Kuhio Beach hulu evening show which seems to be only on a Saturday evening.

in Oahu, the Bishop Museum is also another possibility.

Definitely Bishp Museum is an excellent suggestion! I didn't include it because I only listed places I have been myself. Pearl Harbor, Arizona Memorial, the Zoo, the Aquarium, a luau, would be others to consider (things people do but I have not been yet).

Check the schedule at Royal Hawaiian center because they have something going on most days of the week https://www.royalhawaiiancenter.com/events

Here’s a full day downtown Honolulu:

Reserve Iolani Palace tour about 11am.

Reserve Shangri La tour 3 pm

Reserve MW Restaurant about 6:30 pm

Uber to Iolani Palace, get there early to check out Mission Homes District, Kawaiahaʻo Church, Kamehameha statue, Capitol.

After palace tour walk to Bo’s Kitchen for lunch, then walk to Honolulu Art Museum, check out art exhibits waiting for Shangri La bus.

After museum walk to MW restaurant, Uber back to Waikiki.

You need to make reservations well in advance for the ShangriLa tour and it is not available every day. Tours are very limited in size, days, times. I would never try to do Iolani Palace and ShangriLa on the same day, that's not likely to work. For iolani Palace the morning are docent lead tours and the afternoons self-guided audio tours.

I did this schedule at these times in January, plenty of time really. Walked through the whole palace basement museum too. Got it all done (did not do the Mission Homes tour) without rushing, and just walking between things. It's nice to do the short walks away from tourists. The Capitol is a quick visit.

What do you mean by just "walking between things"? To see ShangriLa estate means joining a tour that leaves from the museum with a couple vans which drive small groups out to the estate at given times.

Did you make reservations for both of these in advance? Just curious, mahalo.

Yes made reservations at least 2 months in advance.

By walking I meant the immediate downtown area connecting the sights and the Shangri La shuttle. I did have time to view the entire art museum, the best sections are the China, Japan and SE Asia collections. The restaurant at the end was a high end, mostly locals, place.