Well, DH and I provide a lovely home for our DC. They have space and privacy to do their work and revision and of course a plentiful supply of cakes.
I expect them to take full responsibility for their own learning. I do make suggestions about revision, sometimes when I'm not even asked, but I really do try to let DC organise themselves. And on the occasions when it has all gone wrong, because teenagers know far more than any adult, we have been there to help them move forward.
Exactly my thoughts WW
I would add to that 'just be there'- a throwaway remark from one of mine recently made me realise how much they just like/need to feel that you are around, doing 'mum stuff' and, I guess, making their world feel 'right'. I've reorganised my diary a bit during the exam period so I'm not away overnight, though of course not everyone has this flexibility so I'm lucky.
And yes, food very important- decent meals, a ready supply of snacks and baking too. I think the smells from the latter (usually!) are comforting for everyone, and stressed siblings benefit too.
And finally, though harder now that going outdoors involves the risk of being blown away, hit by tumbling structures loosened in gale force winds or washed off one's feet by deluges of incessant rain- fresh air and exercise always good too, and not just for the students.