We typically go for 10 days each year. We still tend to over pack but this has been working pretty well.
I pack 5 bottoms in solid colors that will mix and match well plus we are all wearing one.
Pack 8 tops for me and DD and 9 for DS.We all get a new one to wear home on plane.
DD and I pack one dress.
Pack 10 underwear and socks plus one pair flip flops or sandals and
Crocs and wear sneakers.
I pack 2 bathing suits and use hotel shampoo to wash out in sink and dry on the clothes line in tub.
I wear a light sweater,jacket or zippered sweatshirt on plane that can be worn at night if needed and kids do same.
We carry at least one outfit,flip flops and bathingsuit in carry on in case lugage is ever misplaced,again.
I put the kids outfits in XL Zip locks and that way they get dressed quicker,pack easier and go into hotel drawer in a snap.
Toiletries and meds were something we took carry on. We are going to have to pack in checked bag now which will likely mean one more checked bag since I dont want shampoo on my clothing.
Weigh the bag before you go because the airlines charge for heavy bags. We made it last year by 2 lbs because I weighed it already.

I wish we were going NOW!