A friend gave me good advice on packing. This method is the Most Critcial first, and then work your way backwards from there.
She said you first fantasize dressing yourself from naked to your final main outfit and place everything on the bed.
Like underwear first, then socks, then pants, then shirt, etc.
Once you have the main outfit layed out on bed, then just replicate it with however many copies of outfits you need. Lets say 3 sets for a week.
Then, throw in extra pairs of underwear and socks ONLY for the extra days because the outfits can be re-used, but underwear cannot.
Then go right to main KEY things like billfold and/or purse, money, passport, etc. which are your main key items that you absolutely have to have to get on and off plane and rent a car. Once you have those things,
Then, it is just a matter of the extra hygiene products like toothbrush, combs, etc.
Dont pack the suitcase until everything is out and you are all done because you dont want to have to try to remember if you packed it already. And if there are any items you need to use during the day before you leave, just write those down on a piece of paper and be sure to pack them before you leave.