Taxis are the most convenient direct way to get from point A to point B in Shanghai. You do not need to tip your taxi driver, it is not common practice. Taxis are equipped with a meter that is pulled down when your destination is settled. There are several taxi companies in Shanghai, and companies are denoted by their logo and also color of vehicle. Most taxis are Santanas, a vehicle made for China by Volkswagon. Da Zhong and Qiang Shen taxi companies (the light turquoise and golden yellow taxis) have a list of service standards in Chinese and English in the back of the taxis. The base fare is 10RMB ($1.25) and increases by 1RMB every kilometer after the first 5 kilometers. The rate is slightly more expensive after 10PM. Taxi drivers do have a rating program, and neat the meter display on the dashboard may have a light up plaque with one to four stars. These are based on service standards, a clean driving record, and in order to get the fourth star the driver needs to be competent in English. Your driver may consult a map if your destination is not one of the bigger hotels or more well known spots in the city, but be patient as it is nearly impossible to memorize all the roads in the city. If you are in Pudong and going to Puxi or vice versa, be sure to let the taxi driver know as soon as you get into the vehicle as some taxi drivers do not like to or will not drive on the other side of the city. This is better for you as a customer because in many cases the driver does not want to go somewhere if there is a risk of getting lost and having an angry customer. Be sure to collect your receipt from the driver, regardless of if you are paying in cash or with a transportation card as this is the best way to identify a vehicle if you forget something in the car or have any problems with service. Taxi companies do have toll free numbers printed in the car and often on the outside as well. A pickup can be scheduled by calling ahead.
Avoid any taxi's with a license plate beginning with the letter 'X.' These are unlicensed, private taxis and the drivers do not adhere to the code of conduct required for licensed taxis. In general, you will not encounter these taxis in the main tourist and shopping areas, only in outlying areas.
It is possible to rent a car in Shanghai. There are international rental both at the Pudong Airport and in the city. The issue here is one of practicality. An international license is not sufficient to drive in Shanghai. You need to get a Chinese permit, and then go through the licensing process which includes a practical course and an examination. It's not difficult, though expensive, if you live there for an extended period of time (at least a year), but there are so many other options for transportation that it seems unnecessary.
