Take a compass. I would park at one of the subway stations then ride into downtown. I'm usually really good at directions but when getting turned around underground then coming up on to a street corner thats labeled A and second then looking at the map ans seeing they start at A in the center and go B, C, D, etc to either side and likewise first then second and third, etc each way I'd have to walk a block each direction to see if the street names were incrementing or decrementing to determine which direction I was actually going. I would know which A and second I came up on but would have to walk to thrid to tell if I was facing east or west for example.
Also everything is on .gov hours, i.e everything closes around 4:30-5. I planned on doing my work during the day and then visiting things in the evening but didn't get to see much except from the outside because of everyting being closed.
Don't be alarmed to see people sleeping on benches and such, it seems there is a large homeless population but they never bothered us, it was all the other tourists that were rude. And don't bother being polite, if you step back to let someone off the train before shoving your way on other people will just shove their way in front of you and you'll miss that train, you just have to shove your way in with them. And about half the people would jump the tunrstiles and ride for free.