Hello Venkateswarlu

The most common and the most important advice as far as biology is concerned is READ NCERT COVER TO COVER.

One more thing NCERT is important  but remember NCERT is not sufficient, because the paper is made by CBSE and their syllabus is NCERT .But some questions Come other than the NCERT .By the studying NCERT thoroughly from cover to cover you can surely get 280 to 300 marksBut If you want to get a medical seat in a reputed govt college then You need to score 330 + in biology. So to score 330+ you need to prefer some reference book.

Truemans Biology Vol. 1 & 2

Objective Biology by Dinesh

Pradeep Publications Biology. You will prefer

One of them. 

Do only revision of your notes or what you have studied.Focus only on important topics like:-

)Biology

Pay attention to Princilples of Inheritance and variations.   

  Cell The Unit of LIfe.

  Biological Classification.

  Morphology of Flowering Plants.

 Sexual Reproduction in Flowering Plants.

 Basis of Biotechnology, and anatomy.

 Genetic.

 Ecology and Environment.

Also to score this much you need to solve lots of mcqs and take mock tests regularly. Then definitely you will be able to score at least 330+ marks.

Regards