communication is key
in each case, we've had a really honest convo before any plans have been confirmed, to make sure we're on the same page. not everyone travels the same, and that's totally fine - that's what makes us all wonderful humans, but you can't expect two or more people to get along like a house on fire if everyone's not on the same page. you like to chill by the pool but they're an adventure seeker? chances are that if that comes out in the wash mid-holiday, there could be trouble. so, lay your cards on the table up front, that way compromises can be made, and everyone gets what they want out of the same holiday. i know people who don't like confrontation, but it's easy to pre-empt that with loads of open and honest communication from the top.
make a plan to make a plan
there's nothing worse than the "what do you want to do?" roundabout. it's cool if you're not bothered about what to eat or what to see next, but there's nothing i loathe more that being told "i don't mind; it's up to you; if you like". like, no. i'd travel by myself if i wanted to make all the decisions myself, so what i try to do is consider a rough outline of a plan (in a spreadsheet because i'm a loser like that), considering things like: proximity to hotel or airport, cost, and whether tickets need to be booked in advance. that way, everyone can feed into what is or isn't of interest to everyone, so there will always be something "on the list" that is agreeable to everyone, and absolutely zero need to utter the words "yeah babe, whatever you want".
agree to disagree
no two of us is alike, and we all come from such different backgrounds that no two (or more) people are going to get on all the time. there will always be something, some topic, that can steer conversation into a dangerous territory, and it's absolutely okay to throw out: maybe we shouldn't talk about this right now, let's agree to disagree on this one! that way no-one is right or wrong, and no-one's feelings are hurt when a conversation gets heated or borderline argumentative. when you're in close quarters for an extended period of time - even with the most chill of people - there is bound to be something that can cause some upset; drop it, and carry on having a banging time.
take a break if you need it
because you cannot always be "on", right? it's important to remember that time to recharge from socialising is as important as the whole holiday, so allowing for some down time can really help. whether it's an hour or so back at the hotel before dinner where you can rest up, have a shower, charge your actual batteries, or have some quiet time, it can make all the difference. pushing through when you're not feeling it can be rubbbbbish for everyone around you, because your mood will dip, your enthusiasm will drop, and it will rub off on those around you. an hour of quiet can honestly make all the difference.