Avoid the airport lines by doing as much from home as possible, like checking in online and printing or e-mailing your boarding pass. If you can fit all of your things into carry-on luggage, then you can get through the airport so much faster.
Next time you’re at the airport, take extra copies of other forms you often need to fill in. For example, whenever I travel to the US, I need to fill out a departure record (white form) and a customs form (blue form). The extra copy I took last time meant that I could fill in the form at home, then just grab a few more on my way through.
Also: if there’s an alternate entrance for a popular attraction (such as the subway entrance for the Museum of Natural History in New York), take that instead of the main entrance. The lines are usually much shorter.