Gate A has a BestBuy Express near the X-Ray if you forgot to pack your cell phone charger or for a long haul flight, a noise canceling headphones for some quiet and non-fatiguing rest on board.
Once your flight starts getting delayed - forget about it & get a rental car if less than 8 hour drive ... The queue system is rough & weather (even minor) just crushes LGA
If you're traveling on American in Terminal D, eat before you get here. There aren't any good places to eat or grab a cup of coffee. You'll be stuck with Aunt Annie's and bar served coffee.
Construction and congestion is terrible. If departing/arriving in the afternoon or evening plan lots of extra time, check your flight for delays, and confirm your terminal and gate carefully prior.
Arrive a full hour and a half before your flight. 30 minutes to check in, 30 minutes for security and 30 minutes to get to your gate and get seated. Oh and don't fly AirTran, it is awful.
If you're going to take the bus and you don't have a Metro card, you'll need change. The buses do not take bills. (At Terminal C there's a change machine and Metro dispenser right of baggage claim.)
Would you like to try Obama's favorite burger when your traveling thru NY's LGA Airport? Go to Five Guy's Burgers and Fries in the central terminal before security at the American Airlines gates.
The line at my taxi terminal was crazy long but the other two terminals just a couple hundred feet away had no waiting so it may be better to just hoof it to the next taxi station.