Hello Hardik! Here are the places to visit in Delhi:
Qutub Minar
Lotus temple
Akshar Dham
Hauz khas village (visit before 5 PM to watch the park and after that you can visit cafes later in the evening)
Bangla Sahib Gurudwara, CP
Connaught place (in the evening before it gets totally dark so that you can enjoy better without getting cold)
CP
Hauz Khas Village
Historical Monuments like qutub minar,Humayun tomb etc
Chandni chowk
Bangla Sahib
India gate
Street food
Agrasen ki bawli
Akshar dham temple
iskon Lotus temple
Tho people think old delhi isn't good but i'll say it's the best because you will get varities of street food. Paratha wali gali is the best, try to visit it on both evening and morning time. another place is Jama Majid situated in Dilli6, this place is Heaven to me because i never feel any bad thing when i come across it, I call it my "Sukoon Ghar". if you come to Delhi in winter time then do reach Yamuna Ghat before sunrise and stay there for around 2 hours. this place is full of Siberian Seagulls and is amazing. it's located 15mins walk to Kashmere Gate Metro. you need to search "Kashmiri Ghat (No. 25)" if you want to locate it on Map. Hope it all helps. Have a wonderful time.