Summarize the following:
You can check out which route you want online and print out directions. However, you can also buy a pocket-sized map at most bookstores and even convenience stores to make it easier on yourself. You can use the Metropolitan Transport Authority's trip planner at http://www.mta.info/nyct. For instance, you can put in your departing address, landmark, or station name and the address, landmark, or station name of where you want to go. You can select just the bus or the bus plus the subway to get you there, as well as a departure time. Then the system will return itineraries that will get you where you need to go. Work out which buses you need to take and where you need to change buses. You want to know before you get on the bus so you don't get lost or get off at the wrong stop. If you use the trip planner online, it will tell you where you need to change buses. If you're just using a map, find the bus stop where your route meets the route that goes to your destination. That's where you'll change buses. Sometimes, you can find a direct route, too. Figure out where your first bus stop is based on the route you've planned and head that direction. Look for a bus shelter, or at the very least, a round, blue sign that has a bus and the route number on it. The bus stops will be listed as part of your route when you look it up. Plus, you can look at a map of bus routes to locate bus stops. Just because you're at the right bus stop doesn't mean that every bus is the one you need. Buses from different routes will stop at the same bus stop, so check to make sure you're getting on the right bus.

Summary:
Get a map. Figure out your route. Find the bus stop. Check the bus number as the bus pulls up.