One thing one should not miss is a visit to the many amazing viewpoints around the island, Promthep Cape is famous for it’s spectacular sunsets, and there is plenty of viewpoints on the road from Patong Beach to Rawai Beach one should enjoy. As well as one on the way to the Aquarium in Panwa, from which you can see most of the eastern part of the island.
One show most people wont miss is Phuket FantaSea Show, it’s one of those rare event’s that will leave you with a very memorable experience. Just make sure to get good seating, it does make a difference.