I've talked...a lot...about packing lists. To me, they're invaluable.
If you travel a fair amount, also keep your 'go bag' of toiletries packed and ready to go. I don't care whether you jet off to Europe or go to Tahoe for the weekend. Having that already packed and ready saves a bunch of time when packing.
You also have less chance of forgetting to take something important...like an extra set of contact lenses, vitamins, or your favorite travel hair products.