The past few years I’ve tried to make the airport experience smoother by keeping my passport, tickets, and boarding pass together and easily accessible. I used to just used an old envelop but now I have a small plastic wallet (about 18 x 25cm) to store it all. I also have a tendency to be incredibly protective of my passport when I am going through security, then chuck it somewhere when I get on the plane, and flap around trying to find it again when I land.
Obviously, I always get some currency for the country I am going to before I set off but one thing I do now is to make sure I have some of my usual currency (GBP) to pay for a taxi to the airport or food and drink at the airport. And I keep the two currencies separate, either in two purses or separate pockets in my purse.
It’s always a good idea to take some extra underwear in your hand luggage in case your bag gets lost, and some toothpaste and a toothbrush for the same reason. But I also like to take some shorts, if I can fit them in, as I tend to travel in jeans to a much hotter country and want to change right away. Conversely, if you’re travelling to a colder country then take a cardigan or jacket with you.
Quite often I purposefully book early flights so I get the most out of the day that I arrive at the other end but my accommodation will not be ready for check-in until 2pm. So I have to stow my stuff somewhere, either in a locker or leave it at the hotel until I can check-in properly. My hand luggage bag is always bigger and more cumbersome than what I want to carry around with me everyday so I put my smaller day bag in my hand luggage, and put my phone, purse, camera etc in it. So when I dropped my stuff off I can just grab my little day bag and go, rather then spend 30 mins shuffling all my stuff around first.
You have to be careful with food in your hand luggage but something like a cereal bar or crisps should be fine. Usually, I end up getting up quite early and not really being in the mood but by the time you’ve taken the bus/train/taxi to the airport you might have already been awake for several hours, factor in the time it takes to get through airport security and you’ll be ravenous and force to pay the airport premium for food. I also take a drink with me sometimes, and just drink it before I head through security.
When I come home I usually have more than one bag to go through. I empty the bags out and make sure to check every pocket of every bag before putting them again as you can easily leave something like money or your passport in a pocket somewhere.