You can go to Holiday Beach to have a look.That's public beach of local people.There's a golf club there,if you like you can play there. Walk along with the coastline,you will passed Haikou Bay.There's some hotels on building and there's a yatch club but not opened yet.You can have a cup of beer at seaside bar at night.Great.Also you can go to therater to have a performance named Impression-Hainan Island.You will be impressed.You can also play Golf at west beach.
There's many hotels of different rate from 120 to thousand,you can choose anyone as you wish.
It's party time during night.What I recommend most was a snack named Qingbuliang.It's such cool dessert in such hot summer.:)
Enjoy Hainan.Any questions about Haikou,you can ask me.