Never be afraid of asking questions. If there's anything you don't understand - even if you think it's silly - don't ignore it! Ask your teachers or friends for help. If there's nobody to help you at the time, write down your questions in a little notebook so you remember them when you go back to class.
When you're planning your revision, give yourself a wide margin for adjustments. Don't feel guilty or angry at yourself if you can't stick to your plan... It happens to us all! Simply make the necessary adjustments to your timetable and always set your eyes on what's ahead, not on what's past. As my grandma used to say: "Le temps perdu ne se rattrape jamais!"
Remember that everything that you do has an opportunity cost. For instance, I know that the 30 mins I spend scrolling down my Facebook newsfeed in the morning can be better spent doing other things (including sleeping more)!
If you lack motivation, remember that every month's work can be worth hundreds of thousands of rupees! :)
General paper. This might not apply for everyone but still. If you do not treat GP as a main, it can be costly. Often we neglect the Paper 2 i.e data and comprehension. In my opinion, it is the most decisive paper. Work as much P2s as you can, be it from other variants.
When I was at school, there was a book by Ah-Teck and Mungur that had exam papers similar to - but slightly harder than - Cambridge A-Level papers. I strongly encourage you to work your way through the whole book (after you complete your syllabus). (P.s. There is no conflict of interest)
Make an extra effort to understand the theory behind your practicals.
Do not limit yourself to one textbook. You will certainly get a better understanding of concepts by reading different textbooks and even watching videos on youtube.
General Paper and French Sub
Try to read at least one newspaper article (e.g. on bbc.com or Lemonde.fr) every day. Read slowly and pay attention to sentence structure, expressions and vocabulary.