I do the Edexcel spec but this advice applies to all exam boards in my opinion:
watch videos (freesciencelessons or Miss Estruch are really good) and take down notes from there. Make sure to write the notes in your own words. Then summarise the practical in simple terms so it becomes more clear.
After you have done this, do a lot of past paper questions and check the mark scheme to see where you messed up, and write down the mark scheme answer for those questions so you don't repeat the mistake.
Hope this helps <3