I was in delhi for about 2 years so sharing with you some of the places I visited & also near by places
list of areas for shopping
Cannought place(CP)
palika bazzar
Lajpat Nagar
Sarojini Nagar
Chandni chowk
guffar market
Nehru place(For electronic items)
janpath
GIP(Great India Place)
List Of Historical & good places to visit
Lotus temple( Near nehru Place) & on the way you can visit ISKCON temple also
Redfort
India gate, Rajghat, parlament house, Rashtrapathi bhavan
qutub minar(Lado sarai bus stop)
Akshar Dham(Dont miss boat ride& fountain show)
Zoo(Beside Pragati maidan)
Noida, Gurgaon.& various shoping malls
Places Near By delhi
Agra(If you are on mathura road go to badarpur border where you will get many cabs towards agra)
Mathura, brindavan
Shimla(Have to travel a bit more), for shimla best way to go is, from delhi go to kalka through train & from kalka you will get a train which is specially made for shimla hilly areas.Dont miss horse ride in shimla take a guide in shimla.
Mussori: there are many buses from delhi to dehradun & from there you will get cars on rent to mussorie
Jaipur: Another historical place have to visit the famous hawa mahal & many more.
Best Place to visit delhi is from Noveber to january.You will get chilling weather in this period so enjoy the weather in this period.
For shimla & mussorie keep an eye on weather report when snow fall will occur & apart from this best period is January.
Best means of transportation: DTC(Take day pass of Rs 40 & roam in Red AC Bus)
Metro & cycle rekshaws.