Hello Lakshmi,

Here are some tips from us which will help you:

• A proper timetable/study plan is necessary to keep up with the portion
• NCERT books are very important and one must complete them first as they clear teh basics and help you to visualise things rather than mugging up.
• Time management is very crucial for the exams as well as mocks so start prepping up well and keep a track of time.
• you should prepare the previous year papers as you get an idea about how the papers are going to be.
• Consistency is a must and keep working hard for it.
• Conceptual learning is very important as mentioned above rather tha mugging up
• Mock tests are a must as they help you overcome as well as analyse your mistakes.

Below I've complied some important chapters for you from physics,chemistry and Biology:

PHYSICS:

• Introduction & measurement
• Rotational motion
• Description of motion in two & three dimensions
• Gravitation
• Oscillations
• Laws of motion
• Magnetic effects of current

CHEMISTRY:

• Basic concepts in Chemistry
• Hydrogen & the s block elements
• Atomic structure
• Organic Chemistry – Hydrocarbons
• States of matter
• Chemical Bonding
• Chemical Kinetics
• Purification & characterization of carbon compounds
• General principles & processes of isolation of elements
• General organic chemistry

BIOLOGY:

• Diversity in living organisms
• Biology & human welfare
• Human Physiology
• Biotechnology
• Ecology & environment
• Genetics & evolution
• Cell structure & function
• Structural organizations in animals & plants
• Plant physiology

There are many more but these are the important topics you need to keep an eye on.

If you have any doubts, feel free to comment down in the comments section below.

Hope this helps and all the very best to you!