Fortunately, there are maps at every station to help navigate this complex system. Here're guidelines I made for myself:
- Find the station you want to travel to. Look below the station name. There, you will actually find the designations of the trains that will go there. For instance, 42 St Bryant Park has the letters B, D, F, V under it. Those are the trains that will actually go there. I didn't realize this all through my first weekend here... it's a wonder I actually got to where I wanted to go!
- Now, you just have to figure out what connections you need. Don't assume that you just have to cross the platform to make a connection! Sometimes, you have to go up/downstairs. Sometimes, you have to walk to another station to make the connection. This is where reading signs is extremely important.
- You also have to read some other signs. Some trains run differently at night or on weekends.
- Have a map with you! I picked up a tour pamphlet in the lobby and it shows the stations in Manhattan, and has been really helpful for the places I went. I think you can get a full map at one of the bigger stations.