Not sure what you’re interested in, so i’ll leave some typical ones.
Cultural Heritage Areas – Bras Basah/Bugis/Arab Street, Chinatown and Little India
Parks and Reserves – Gardens by the Bay South (Recently opened), Botanical Gardens, Night Safari (1st night zoo in the world)
Shopping Areas – Orchard Road and the malls around the circuit (Suntec City, Marina Square, Raffles City)
Night Spots – Clarke Quay and Boat Quay
Museums – National Museum of Singapore, Asian Civilisation Museum, Singapore Art Museum
Entire Island of Attractions – Sentosa (where Universal Studios Singapore is located as well) [Has good beaches too]
If you have certain preferences, i may be able to help more specifically.