Nowadays, with all the extra security on highspeed trains and airplanes, it is useful to travel lightly. Only pack hand-luggage, so to speak.
Long years of experience in travelling have taught my sister and I how to travel with the least amount of luggage. And our suitcases are packed in a couple of minutes. I don't even need a list.
Important is, you only bring what you really need. You don't need ten dresses or t-shirts a day. In our case, we take underwear for as many days as we're away (with one set extra, because you never know). Same goes for the t-shirts. Then take a pair of shorts/trousers/skirts that is easy to wear and suits with the colors/design of your t-shirts or blouses. For a short trip, we only pack one pair of shoes or sandals in the suitcase, plus a pair of bedroom slippers. Last item in the suitcase is a nightshirt or pajamas - and of yes, a bathing suit if you go to sunny places.
We've managed to downsize on our luggage so we can always travel with carry-on luggage only. One (small) suitcase, and a big sack aka handbag. But the sack can carry a pair of shoes, underwear, a laptop and e-reader without problem. It's handy when your handbag (sack) has compartments, in which you can place your travel documents and all those items which need to be taken out at the scanner. I put them into plastic bags already, so they can just be plucked out.
The big advantage is you can easily carry your luggage (handy when you have to climb stairs, like you have to do when going from the railway station in Zaventem to the departure hall) and it's no problem when having to walk a while.