To dramatically improve your airport experience, grit your teeth and do what you must to unclutter your carry-on bag. An x-ray image of an uncluttered bag is much easier for security personnel to read. If possible, pack all liquids, aerosols, and gels in your checked luggage, not in your carry-on. This avoids additional screening. The same goes for overcoats and jackets. If you carry them with you through security, they have to go through the x-ray machine.
While you're waiting in line, make use of that time to prepare for the metal detector. Bring slip-on booties to allow you to remove your shoes ahead of time, ready to place on the belt as soon as you get to the x-ray machine.
Collect all metal objects from your person, such as jewelry, accessories, keys, coins, mobile phones and pagers, and have them ready to drop into the plastic bags provided. Or bring your own plastic bag. If you are wearing hidden metal, such as body piercings or knee replacements, save time by letting officers know before going through the detector that you will need additional screening.
While in the security area, have your airline boarding pass and a photo ID ready to display. If you can't find it when requested, you will have to undergo additional screening.