Money
If you have time, get a Revolut card, as it doesn’t charge extra for paying in a different currency. Halifax also does a credit card that has the same benefit.
I never change cash these days as can pay on card everywhere.
Travel docs
If you haven’t paid for seats together, check in for your flight as soon as check in opens (make a diary note). That way you are more likely to have seats together.
Take a copy of insurance policy and claim phone number. Take passports and check validity.
NB EU rules say passports expire 10 years after issue- check your passport issue date as well as expiration date, as the UK govt sometimes issues them to last 10 yrs 6 months or so, but the EU won’t recognise those extra 6 months.
Packing - useful items that are easy to forget
Chargers and adaptor plugs. Remember chargers for eg toothbrush/headphones not just phone.
Medication (in hand luggage ideally).
(Remember hand luggage can’t have any liquids over 100ml.)
Sunglasses
Earplugs
card game
Headphones
Agree a basic first aid kit is useful- nurofen, calpol, plasters, imodium, piriton. Yes you can buy this all there but it’s just easier to have it to hand
Agree that you can reduce clothes by half! I always take too many.