Even the most forgetful can benefit from the camera on their cell phone; you can use it to remember where you parked , or, some new prospect you met last night  when your memory was a little clouded.
My next tip is one that's great for traveling, especially if — like me — your suitcase rarely ends up meeting you at your final destination. When you're frazzled and filling out those lost baggage forms, sometimes you forget things you packed, especially things you packed that would be right on top and identifiable. Which, if you've been in the situation, you know you need to fill out.
Save yourself the hand-wringing and take a shot with your camera phone of your packed bag, just before zipping it up. Whether this will get your bag back to you sooner, who knows, but the less stress incurred while flying, the better.