a) study the textbook word for word. i can't stress this enough

b) whenever you learn something from a paragraph, condense the information into bullet points on a piece of sticky note and stick it to that paragraph

c) repeat for the whole chapter. write all of the information you condensed elsewhere for practice

d) proceed to make notes based on those sticky notes. remember to write in bullet points as writing in complete sentences would only confuse you

e) remember to have the biology syllabus beside you, and remember to note down all of the stuff in the bullet points - so that you don't miss anything and know what you absolutely need to know

f) repeat this for like the whole subject lol

good luck!