I'll try to list a few places for each
Local food:
Liliha Bakery(Liliha location not the one on Nimitz Hwy)
Rainbow's Drive Inn
Waikiki: Lot's of places to eat depending what you're looking for
Restaurant Suntory(teppanyaki and whiskey)
Arancino(Italian, uni pasta, squid ink pasta, squid w/ mentaiko pasta)
DK Steakhouse
Lot's of bars(Buho is a chill rooftop bar. Rumfire, Dukes, Moana Surf Bar if you're trying to be near the beach. Kelly O'Neil's if youre looking for a no frills place to drink, one of the only spots you can also

)
Cheesecake Factory
Hawaiian food:
Highway Inn(I like the Waipahu location but there's one in town)
Halena's(more popular with tourist)
Korean:
Kyung's Seafood(good if you want to add poke to your korean plate, also good place to drink at night with a larger party)
Korea House(yakuniku, adult entertainment next door

)
Millions(good if you're eating by yourself, also has yakuniku)
678(yakuniku)
Filipino food:
Julie'z
Thelma's
Elena's
Jollibee

lol )
Vietnamese food:
Pho Huong Lan(best pho)
Hale Vietnam(good pho)
Pho One(ok pho, best rice plate)
The Pig & The Lady(ok pho, Laotion fried chicken is

)
Chinese Food:
Lam's Kitchen(order the beef and tendon soup, either with look fun or mein. I like mein noodles better)
Little Village Noodle House(volcano pork chops, mother of all fried rice)
Lot's of other places but not really for just 1 person
Japanese/Ramen:
I-Naba(best soba and tempura, ok sushi)
Izakaya Torae Torae(my favorite sushi bar)
Menya Musahi Ramen
Yotekko-Ya Ramen
AGU Ramen
Hokkaido Ramen Santouka
Lucky Belly Ramen(good if you're going to stay for drinks)
North Shore:
Shrimps Trucks(I like Macky's for the lemon pepper, Giovanni's for the garlic w' spicy sauce on the side.)
Storto's(grab yourself a sandwich, do half only tho. full is like 14"s and 1/2 a lb
Go swimming at Waimea Bay unless there's waves, it's summer so it should be flat.
Shave Ice:
Shimazu(best on the island, don't believe anyone that tells you different)
Monsarrat Ave Shave Ice(not as traditional, fresh fruit syrups and japanese style toppings. in the little crack next to Pioneer Saloon)
Frost City(taiwanese shave ice)
Poke:
Literally everywhere
Fried Chicken:
Vons Korean Fried Chicken(get the crispy fried shoyu, god level stuff)
I recommend doing most things in the morning/early after noon like 8am-3pm if youre trying to avoid traffic. don't try to go to the westside after 3, well dont go there at all.