Hello dear,
As you are of science student, that's why you need ti give more time to study so that you will be able to complete your syllabus at time and will have enough time to revision at the end of the exams.
And of course consistency is must which will help in your class 12th.
Thank you

If youa re in your 11th right now, we assume that you will be appearing for NEET 2021/22. The MHRD did announce that NEET 2021 Syllabus is going to be reduced and revised. And so when you appear for NEET 2022, the new syllabus might come into force which has not been announced as yet. And we are expecting the new Syllabus to be rolled out in the month of December.  So the best plan for now is to stick to NCERT books. You can alloot 1 hour per subject and 1 mock test a week and that should keep you updated with the required knowledge for now. Once the official syllabus has been released, you can focus on those topics. And if you plan on studying 3 hours a day apart from your Regular classes, there is something called PATS method that can help you in effective preparation:

Picking the Best Environment for you to study: This is important because you should feel secure and comfortable but not too comfortable where you might fall asleep.

Always reducing the visual distractions: Make sure you have nothing within your vicinity to distract you. Like keep your phone a side. Or sit away from the TV, Windows where you can see people.

Try to Eliminate Noise around you: If you are someone who can concentrate with music, make sure it is light music and nothing to distract you. It should increase your ability to concentrate and not distract you. If there is any noise that might distract you, use ear plugs or a fan. Trust me, if am being distracted by noise, I switch on the fan and it works.

Self talk to control Internal Distractions: When you are noticing that the mind is drifting aside, stop what you are upto and keep a checkmark on a piece of paper along with the time. Keep a track of these checkmarks and the timings. Talk to yourself that you understand you are being distracted but you also have to study. If it keeps bothering you, write down what is it that is bothering you and promise yourself that you will come back and look into that. Now that has been parked in the notebook, get back to studying.