1) Garden of 5 senses (very peaceful and a lot to see)
2) CP (needs no description)
3) Raisina Hills & Rajpath (Rashtrapati Bhawan area, go in the evening preferably)
4) Lodhi Art District and Lodhi Garden (Beautiful wall art)
5) Hauz Khas Village (Amazing pubs, cafe's and stores, and do not forget to visit the Lake at the end of the market along with the ruins, it's a perfect sunset spot!)