Okay so, first of all, make your own schedule and find your own way of learning the material. If you have a shit teacher it's gonna be hard but it's doable. The way that I study for chemistry is:

• Read the textbook (Favourite textbook: Pearson)

• Read it again the second time, and this time make notes. Take notes really slowly and make them as good as you can, try to reword everything so it sticks in your head. Include worked examples. Colour coding can genuinely help, my colours are red for definitions, green for keywords, blue for equations, and purple for recall or a side note. I'd highly recommend at least having a colour for keywords.

• Some people say they prefer digital notes, I say avoid it at all costs. Handwritten notes will help you learn the material better, they'll help the information stick as you write it. Also, you'll take longer writing handwritten notes, and this will help you spend enough time on a topic rather than breezing through it.

• Draw diagrams. It doesn't matter how shitty they are. Don't waste time on pretty colours or anything, just make sure you have the idea down, it'll help you understand the concept. This is especially useful in redox, imo.

• If you have any doubts or are confused, don't let that sit, don't push it away. You have the whole internet at your disposal, use it. Watch YouTube videos, watch KhanAcademy videos (highly recommend the second one).

• Next, practice questions. This is the most essential part. You have to be able to understand the theory well, but spend time actually applying it. I like to first go through the Pearson questions, then I do the Oxford Study Guide questions.

• Do past paper questions. Those are questions the most similar to the style you'll be tested in in the actual exam, so get practice with those. Questionbank is nice, too.

• Lastly, refer back to your notes at regular intervals. Once you've done questions and made notes for a topic, don't forget about it. Come back to it regularly, do a few questions, read through your concise and organised notes.