Wired offers up a Wiki page on how to Fly Through Airport Security. One of the best points listed and something I always do myself is the practice of putting your wallet, keys, phone, watch and belt into your carry on bag. Anything else metal that can be easily removed should go in there as well, though I recommend that metal jewelry be left at home or already packed in your carry-on bag when possible. Another good tip is wearing shoes without laces, which is also good for the security of your own belongings, since you’re less likely to notice someone taking your bag instead of theirs if your crouched down tying your shoes.
A thought on watches: I stopped wearing mine when I realized the chances of me not having my phone on me are pretty much zero. I honestly haven’t missed it. It’s one less thing to remove when going through airport security, one less potentially expensive item to worry about losing, and now I don’t have a funny little tan line around my wrist during the summer.