If you're a frequent flier, you may want to consider paying $85 for a five-year TSA Pre-Check membership. This program gives you a shot at being placed in a speedier security line in which you don't have to take off shoes, unpack laptops, or subject yourself to the full-body scanner. The new program isn't without its flaws (your privileges may be revoked at any time and the TSA agents at the airport can still choose to send you through the regular line at their discretion), but it's worth the background check.
If you're not registered, Greenberg suggests picking the security line with the fewest people monitoring bags on the conveyor. Two people in front of one screen suggests that one is in training, which will almost always translate to a longer wait time. For international travel, Greenberg swears by Global Entry, a program that allows you to simply swipe your passport at a kiosk to bypass long immigration lines.