Agree with almost all the above; a couple of suggestions about booking which may make the flight less stressful.
Make your bookings yourself so you can consider all the options.
If it's a long haul trip through a hub like CDG, AMS, FRA etc, there will probably be multiple daily flights on the short leg, but only one or two on the long leg. Leave a longish transit time outbound (at least 2-3 hrs) because missing the long haul flight or arriving without a checked bag may be seriously inconvenient (especially if you are going up country or boarding a ship). On the homebound trip book the shortest possible transit time - there's always a later flight back to UK, and if your bag doesn't make it your dirty washing will be delivered to your front door surprisingly quickly.
If it's a short haul flight on a low cost airline, try to avoid the last departure of the day - that's the one that may be cancelled if delays have built up during the day.
Strongly support keeping your vital documents/cards/phone on your person or very close all the time.
And finally, if your luggage never leaves your sight (because it's in the cabin with you) you won't suffer the heartsink of being the last person waiting in vain at the carousel...