Get a map of the streets and the subway lines that is easy to read and small enough to carry all the time. Manhattan is set in a grid of numbered streets that make it easier to navigate, but it is good to know if you are headed uptown or downtown without walking two blocks to find out. Subways mostly run vertically in Manhattan.
Check the addresses you know you will be staying at or traveling to visit. Figure out which subway lines are in the area and where the stops are located. Try to remember the names of the stops along the route you will be using. If the names are familiar to you, it will make it easier to remember when to get off and when you have gone too far.
Buy a Metrocard at automatic machines located in most stations, subway booths or neighborhood kiosks. If the station does not have a Metrocard machine, a sign at the entrance will read "Enter with Metrocard at all times." If you do not have a card and run into this sign, cross the street and check the other entrances to the station. The opposite platform may have a Metrocard machine; they are usually widely available.
Choose the type of Metrocard that fits your trip length. The Metropolitan Transit Authority, or MTA, offers unlimited cards or pay-per-ride cards. Each fare on a pay-per-ride basis costs $2.25, as of April 2010. A one-day fun unlimited card costs $8.25 and is valid until 3 a.m. the next morning, so after four subway trips the unlimited card has already paid for itself. A seven-day card costs $27 and a 14-day card costs $51.50. Metrocards can also be used on local buses and the Airtrain to John F. Kennedy Airport.
Swipe your card at the turnstile. If the machine has read it correctly, a green light will flash and a bell-like sound will play. Often the electronic display will ask you to swipe your card again, or even a third time. Keep trying and the card will be accepted eventually. If not, look for a service booth or a short silver machine, normally placed against the wall, where you can test your card's value.
Go down the steps to the platform. Check the signs above to see if the train you want stops there. Look for the correct letter or number and make sure the train is going the direction you want, uptown to the Bronx or downtown to Brooklyn. When the train comes, look for the letter or number on the outside of the train itself, then step on and find a seat, or hold onto the handrails.