well, I would like to thank you; I've just passed my Bac
you've asked a good question and I think this is the right time to arrange yourself and prepare it physically and more imprtantly morally for the next year
first, you have to calm dow and chillax cuz Bac is no tough exam, it is simply like all the other ones you've had in last years
secondly revision should be started at the beginning of the year so you won't let your lessons stack up and become exhausting
thirdly, you don't have to push on yourself when studying just take it easy and believe me the Bac is so simple it's a piece of cake
finally, and that's the main advise: have fun this summer , enjoy, relax and forget anything about the Bac try to clear your mind and don't take any courses of any subject
you just need some free space to get ready for the next year cuz you'll get very tired if you start to study from now
take care