Visit Humayun's tomb, Lotus temple, Akshardham temple.
If you are fond of local street food and shopping visit Chandani chauk.
Also you can visit Agra and cover up Taj mahal and Agra fort.
Go to Khan Market (Big Chill), Lajpat Nagar (Market), SDA Market (Cafes), Champa Gali (Cafes) , for the amazing food and capturing insta photos and also, you can shop whatever you want from these places. Enjoy.