I generally agree with Martin's post. I travel very frequently, sometimes overseas, and all of his ideas are good.

I travel in good walking shoes/boots. Even though I must take them off, it is not that much of a hassle. I do not want to find myself walking any distance in dress shoes. I always arrive early and try to time my passage through security for when there are fewer people going through. Because I am usually carrying a significant quantity of electronics, my bag usually requires hand searching anyway.

I purchase water as soon as I get through security, usually two bottles. Sometimes, depending on what I am doing and what my carry on luggage looks like, I will carry Nalgene bottles and fill them once through security.