The metro: it is a fast way to get around in Delhi whether you have short or long distances. The only problem is that it can be very crowded during the rush hours. How to get a metro ticket? You can buy one ticket at the station or you can buy a travel card for 50 rupees and then recharge it, with a minimum of 100 rupees. The metro is cheap, the price depends on how many stations you cross. The metro opens at 6 am and closes at 11 pm. Women, don’t be scared, men and women are separated between the coaches. And, you are lucky, the women coaches are never crowded compared to the men’s coaches!
The bus: it starts at 5:30 am and runs until 10:30pm, and is run by the DTC (Delhi Transport Corporation). You can check here your bus route: http://goindia.about.com/gi/o.htm?zi=1/XJ&zTi=1&sdn=goindia&cdn=travel&tm=20&f=22&su=p284.13.342.ip_&tt=13&bt=9&bts=&zu=http%3A//www.delhitravelhelp.in/. The bus is very cheap, the fare for a normal bus without AC is between 5 to 15 rupees, and the fare for an AC bus is between 15 to 25 rupees.
There are several different types of buses, you can make the difference with the color. Green: these buses are comfortable, everywhere in Delhi. The red buses are the air-conditioned version of low-floor buses. The green and yellow buses are standard floor buses. But semi-low floor buses are replacing them, and the DTC adds more white. The blue buses are quite dangerous, this is why they will be out of service in the next few months. The orange buses are the private buses in Delhi, they have the same fare as the non-AC buses. Then, the purple buses are the City Tourist buses. It costs 300 rupees for an adult and 150 for a child. They connect the touristic places, it runs from 8 am to 8 pm.
The taxi: you can book a taxi with the Meru Cab company, calling this number: 44 22 44 22. Or Easycab : 43 43 43 43. They are even trying to offer the Wifi to the clients in the Meru cabs
And then, last but not least, the rickshaw! Very easy to find everywhere in Delhi, it is better for short distances, but if you have time take it whenever you want!