Oahu - Ala Moana and Ward Centers….Eats - Kua Aina, W&M, Alan Wongs (a must) Sam Choys, if your going to the North Shore try Giovanni’s shrimp truck just ask the locals….

On Oahu there is so much to see, do, eat, watch!!!! Lets start with see. You can go to Pearl Harbor, the Arizona Memorial, or climb to the top of Diamond Head Crater for a magnificent view of Honolulu. Drive to the North shore of the island, and if your timing is right, observe some of the world’s biggest waves and world class surfers. Explore Waimea Bay, snorkel at Hanuma Bay and visit the Polynesian Cultural Center.
If you want American food you can go to the strip on Waikiki side and they have all types of restaurants you would see in the 48 states. If you want to try new local food, their are also plenty of places. The best place is L&L Drive-Inn. OMG! so good I miss it!!
The best place to shop would be in Waikiki if you want high end stuff. Or Ala Moana Shopping Center, Honolulu. about 15 min from waikiki.
My favorit place to shot though is Aloha Stadium Swap Meet. But I must warn you. Bring extra luggage! you will find everything that you could want and more!!

I don’t know a lot about Maui but here is a link.
Visit the 1,200 foot high foliage covered cinder Iao Needle, take the scenic and winding road to Hana, visit the rain forest and water falls on the way. Watch the Humpback Whales winter passage on the west shores. Visit the historic whaling village of Lahaina, now renowned for it’s quaint souvenir shops. Drive to the top of Haleakala mountain observation point for a breath taking view of the island, or stroll along the sandy shores of Kaanapali Beach.

here are some food places on Maui..
I hope that yall have the time of your lives.

hard to answer about eating or shopping. those are the two islands that is the most tourist kind. on maui, gotta see haleakala at sunrise. maybe, hookipa park watch the wind surfers and kite surfers, drive to hana and drive around the west maui mountains, very scenic.
oahu, what can i say, go see diamond head, drink one maitai on waikiki beach, maybe go see north shore where the big waves stay waimea bay, pipeline , sunset like that.
all the food and stuff is what ever unless you going be brave and eat ethnic hawaiian like poi, laulau, kalua pig, opihi then go farmers market by ward.