Science is quite easy feel it.
Stick to NCERT first complete it.
Then go for any refrence book. I'd recommend S.CHAND. Do not study it for sake of having marks. You are in 10th so grasp all the basics for future use in class 11 and 12. Study it for the sake of curiosity.
For Chemistry understand all the concepts and try to imagine those and relate with your real life scenarios.
For physics as I know you have electricity chapters Optics and other important topics study NCERT thoroughly.
Always abide by your teachers instructions.
Try to study organic chemisty by a senior student of class 12 he will explain you by analysing your mistakes as he crossed class 10.
Try to make your own notes using NCERT book. Use a pencil in practise copy. Because graphite in pencil is a lubricating agent and you will experience less friction while writing, your speed will be more than original,your time will be conserved and most probably you will improve your Hand Writing.