With GCSEs you might have thought you could get away with doing no revision at all, or just a little bit the night before. Do not, under any circumstances, fall into this trap for A Levels because for 99.999% of people it just won't work and you will fail.
Organise all your paper work and stationery and have a plan from the outset for how the student is going to split and manage their files. Secondly in the summer the student should be really getting stuck into the first modules in each subject. Once you get ahead you never get behind. That is my motto.
Be ready to work hard from the start of the year. Your exams really will creep up on you quickly and it might feel impossible to revise from them efficiently if leave your first bit of revision until Easter. Don't let yourself regret the grades you end up with for the sake of an hour's extra procrastinating every evening.
It helps to try and learn some of the content at home and if you have any problems you'll be able to ask your teacher within the lesson. Don't waste your time and remember the grades you get will shape your future. Don't get immersed with socialising as it'll be the bane of your grades.
Pick subjects because you like them and actually want to do them. If you hate them you're not going to want to revise them as much as the ones you like. Also don't overestimate the time you have until exams start because they seriously come out of nowhere
you won't just be able to breeze through with A-Levels so I'd say don't leave all your revision to the last minute but break it up and do it regularly!