Find the nearest métro station. These are usually marked on a general map of Paris or also on métro map. If you are having trouble finding the closest station, you might ask an employee at your hotel, a nearby business, or a passerby on the street.
Buy your ticket(s). At some stations you may do so at automated machines. One benefit of these is that you can choose to purchase your tickets through any language you are comfortable reading. If the station does not have an automated machine, you can purchase tickets at the ticket counter. A standard métro ticket will cost about $2.50; you can also purchase a book of 10 tickets, known as a carnet, for about $16. One ticket allows travel anywhere within Paris, and changing train lines is allowed. If you will be in Paris for an extended period of time and plan on using the métro frequently, it may benefit you to purchase a money-saving pass.
Pass through the turnstiles. This involves feeding your ticket through a machine. On the other side of the turnstile you will have access to the different lines.
Figure out which line you need to take to your destination and keep in mind that all lines in Paris are color coded. Usually there are large maps of the métro inside the station. Note that a direct line to your destination may not exist, so taking two or three trains might be necessary. Be sure that you choose the correct platform; you may choose the correct train but could end up going the opposite direction from your destination.