Let me list you a few DO’s and DON’T’s so that you are aware of Hawaiian culture. 

Do:

• The island life here is quite cool and calm but it would be great if you follow a few things you need to know so you can fit in and make the most of the Hawaiian culture as possible.
• Please watch your speed - go slow and don’t drive too fast 
• Honking is considered rude here unless you are in a wedding procession. So please do not honk 
• DO Say Aloha, No it doesn’t sound corny at all, well it’s used throughout Hawaii and is good for coming or going. Try saying other Hawaiian words. It’s not that hard. Also, say Mahalo (Thank you).

Don’t:

• Please avoid talking to a Travel Agent who is familiar with Hawaii to get the best deals.
• The internet might not get you a good hotel room or cheap flight, so do your research.
• Avoid coming during the holidays as Hawaii is always more crowded during the holidays. Book flights during the week. Friday to Sunday are the worst days to fly.
• Please do not attempt to go in the water if you see a red flag. These warnings are important to follow in order to prevent injury or death. The ocean can have high waves and strong undercurrents.
• Don’t go surfing on the North Shore of Oahu in the winter when the surf is up. Leave this area for professional surfers and seek a less dangerous beach.
• Make sure you are on a kid-friendly beach if you have kids. There are many calm beaches like the Keiki Beach and the Kamaole Beach.
• Please be aware that you may not have public transportation everywhere. Although you can ride the Bus in Oahu almost anywhere, it’s not the same on the neighbour islands. Consider that you will need to rent a car.
• Remember not to use the expression ’back in the States’. Hawaii is part of the Unites States., so say ’on the mainland’. Local residents who are of native descent are called Hawaiians. Residents who have lived on the island awhile are called Kamaaina. Foreigners (generally Caucasians) are known as Haole.
• You will be surprised if you see people waving their fists with the thumb and pinky extended. It’s the shaka sign that is generally used in place of a wave when meeting or parting. It is a goodwill gesture that says ’hang loose’.
• It’s important that you know your stuff when shopping for Aloha wear. High-quality shirts are made of rayon and not cotton. They have a better feel and look despite being a tad more expensive. Because of the islands’ casual attitude toward dress, shirts are generally worn untucked. 
• Before you walk around the beach pay attention to the yellow speakers attached to poles along the coast they warn of tidal waves. (If you hear them go off at 11:59 am on the first Monday of the month, it’s only a test.)
• DON’T underestimate the power of the surf and the ocean currents. Newcomers to Hawaiian beaches should follow all posted warnings. In general, don’t ever swim where others aren’t swimming. If you’re caught in a riptide, don’t fight the current. Try to swim parallel to the beach until you escape, then swim to the shore.

After the sun sets here in Honolulu there's a lot more you can do - equal to the daytime activities. After all, you are in Hawaii. So it's just not possible to stay out of entertainment, pubs, dance, beaches, islands, and music. Everything is there, from the best of Honolulu's nightclubs to the best of their bars. Apart from that, there's some unusual things you can do with your friends like the 'Party Bike Bar Tour' where they carry about 15 passengers on a party ride and will stop for you in the middle of some notable clubs and bars. To list a few best places that you can visit, the Duke's Canoe Club, Zanzibar, Addiction at Modern Honolulu, Five-O Bar and Rumfire are great recommendations. Apart from that, you can also go cruising to watch the stunning night time view of the Waikiki skyline, where you have some great in-house programs like Polynesian dancers, music from DJs and some great dinner as well. 

• Oahu scenic helicopter flight: This helicopter flight activity will take you on an amazing island which I'm sure will remain as one of your best memories you will take back home 
• Kayak to the Mokes: You can kayak from Lanikai/Kailua Beach which takes about thirty minutes. This beautiful canoe or kayak paddle to the Mokulua is like a breather which takes you to an isolated island. You will notice there are few good cliff jumping spots and the Queen’s bath at the backside.
• Turtle Canyon Catamaran Snorkel Tour from Waikiki: You can Snorkel with green sea turtles in Oahu’s Turtle Canyon. This is the perfect  spot for the resident turtles. You can do Turtle sightings after which you can enjoy lunch etc. 
• Dolphin and Whale Watching Tour in Waianae: Honolulu is more about water sports. Hence, you get to see a lot of dolphins and whales in Oahu. This is an epic tour that shows you the most beautiful creatures of the ocean while cruising along the coast of Oahu. 
• Visit Lulumahu falls:  As you discover Oahu you will come across a grand waterfall right in the middle of the forest its quite a peaceful spot. Here as well you will a hike right next to the Pali Highway which takes only 30 minutes. 
• Cromwell’s rock pool: As you drive through from Waikiki, there's a small and relaxed getaway which you find known as The Cromwell’s beach. 
• China Walls: China Walls is just a cliff edge which is right on the east side of Oahu. Here you may come across some small to medium cliff jumps on a calm day
•  Halona Blowhole: Please visit The Halona Blowhole which is on the east side of Oahu and is extremely famous because as the waves crash into the cliffs under the rocks the water oozes out through a blowhole spraying right up into the air. 

• Swim with sharks: Here in Honolulu, you get an opportunity to be in the water with a shark. Some tour guides can take people out and let them swim with sharks without a cage! Yes, I'm sure it sounds scary, but they haven’t had any injuries or incidents in 20 years of operation. The Sandbar sharks circle around you as you snorkel. 
• Skydive on the North Shore: For all those who love trying something new, you can jump from a plane right above the beautiful azure water and rocky coastline of the North Shore. It’s an awesome adventure and definitely one of the craziest.
• Atlantis Submarine Tour in Waikiki: Something unusual that you can do is climb aboard a 48-passenger submarine and adventure underwater. It’s truly an amazing experience where you get to see sunken warships/planes and marine life surrounding it. 
• Zip-lining at Kualoa Ranch: Here, you can indulge in some activities like zip-lining. It's a short scenic cruise through some amazing surroundings. This can be enjoyed with friends and family.
• Stand up paddleboard yoga: This is something really interesting and different where you can do some awesome yoga watching while watching the sun go down.
• Hike the Pali Notches: It believed that The Pali Notches is one the scariest hikes on Oahu as you have to challenge strong winds on the trail. There are uneven rocks which you have to climb, which can be quite a task.
• Jump off the plank at Alan Davis: When you are at Makapu’u Lighthouse Trail carpark, there is another attraction not too far. Just along the Waikiki coast where you will find wooden planks hanging out over the crystal clear water. 
• Watch a Surf competition: While you are in Hawaii what better to do with your time than to watch competitions like "The Billabong Pipe Masters" and the “Eddie” which are considered great wave surf competitions at Waimea Bay. 
• Parasailing at Waikiki: You can do some Parasailing at The Waikiki which sets on tour and takes you for a ride high up with a scenic view. 

• Clothes, T-Shirts from Hawaii make great gifts. Or you could also buy slippers (flip-flops), shirts, pareos, bathing attire and more.  They’ll be all the more meaningful at home and can help bring your Hawaii vacation back to life.
• If you need to give Postcards you can buy them from Wal-Mart which usually sells these for a quarter or less. 
• The coffee here is locally grown and is available on Kauai, Maui, Molokai and Oahu. 
• Crack seed. It's like a local favorite of Hawaii and a top pick.
• You can also buy some good Placemats and coasters. 
•  Hawaiian Salt as it includes salt rubs with guava and other delights.
• Soaps from Hawaii in the fragrances of coconut, plumeria and hibiscus will take you back to paradise.
• Hawaiian Heirloom Jewelry with beautiful and enduring designs.
• One of the quintessential gifts in Hawaii is a ukulele made from the Island procured wood.
• Macadamia nuts from the island are a must-taste. Take back a few to cook up some favorite Hawaiian delicacies.
• The Lei Flower garlands, which are used to welcome guests to the island paradise.
• Take back some of their pure coconut oil, that can be used for cooking and several other purposes.