I am usually a short haul traveler. I can usually travel with a carryon and I very rarely check bags. So planning for 12 days in Europe was eye opening for me. Oh boy did I make some rookie mistakes.
1. Overpacking- there is this amazing thing called laundry, you can even pay someone to do it for you. No need for 12 days of clothes.
2. Trains, planes, automobiles and stairs?- only pack what you can carry because at some point you will encounter a sitaution that requires you to carry,lift, pull your bags.
3. Make a list- less likely to forget something.
4. If packing multi-bags, try to put what you need the first few days in bag 1, so your not having to shift thru bags every day.
I started with my 2 rollerboards fully expanded and very heavy. I ended up with, having to do laundry at some point. But for 12 days it could have been worse.