Hi,
You can visit Sri Padmanabhaswamy Temple,The Kanakakunnu Palace, Neyyar Dam & Wildlife Sanctuary and The Napier Museum. Shanghumukham Beach is a must visit beach located at a distance of 23kms fr (Read More)om the city center.
You can get more details on http://www.holidify.com/places/trivandrum/sightseeing-and-things-to-do.html
Some of the best hotels in Trivandrum are:
Thomas Resort
Palmleaves Beach Resort
Country Spa Wellness Beach Resort