1. I'd say familiarise yourself with the whole Chemistry study design. Understand the deep roots of what unit 3 explores. The first area of study covers chemical analysis, looking at quantitative and qualitative chemical analyses involving various chemical analytical techniques, including gravimetric analysis, volumetric analysis (looking at both acid-base and redox titrations), spectroscopy, spectrometry and chromatography. The second area of study looks at organic chemical pathways. This includes looking at organic compounds (hydrocarbons) from C1 to C10 (meth- to dec-), and the various alkanes, alkenes and others organic groups. Furthermore, you look at reactions in the organic chemical pathways, including addition/substitution reactions, combustions, addition polymerisation reactions, the condensation/hydrolysis reactions, etc. You also look at Biomacromolecules, including proteins, lipids, carbohydrates and DNA.
2. Practice practice practice. Don't just assume that knowing the formula for calculating the number of moles is sufficient for a 50 (not that you do, just warning you to take heed). You must know the inner depths of your calculations. Understand the theory behind titrations, behind redox. Why do we balance the number of electrons in redox half-equations? Once you know the theory, the calculations become so much easier to visualise. Also, look out for questions you've done incorrectly. Document them, and when exam time comes, refer to these so that you've ensured that you've rectified all your errors.
3. Constant revision, ensuring accuracy, and rectify minute errors that could be the difference between an A+ score that could mean 49 or 50. Doing well in Chemistry requires hard work and dedication, a strong understanding of the theory and impeccable application of it.
4.
Do: understand the theory, answer lots of questions, ask lots of questions.
Dont: underestimate Chemistry.
5. TSFX lecture notes are comprehensive. Mr. Goudie on YouTube also has some good clips called Chemisodes. They are good to watch if you find understanding a particular topic too difficult, and you require extra assistance.
I want to change my attitude to learning chemistry because I know Chem 3/4 is much, much harder than Chem 1/2, and I defs wanna aim for that 50.
Put the 50 in perspective and work for it

Hopefully you get it. Your attitude has already improved by the fact that you are willing to. All the best
P.S. I know you *I sound so bloody stalker-ish. But I actually know you
