In general bio is very much what you can recall and past papers to put it into practise.
Topic 6 aqa notes here (
https://pmt.physicsandmathstutor.com/download/Biology/GCSE/Notes/AQA/6-Inheritance-Variation-and-Evolution/Detailed%20Notes.pdf) - I enjoyed this unit, is there a specific subtopic of it you find difficult? Like evolution or inheritance etc? Meiosis and mitosis?
I remember for evolution I made an acronym (in welsh but I'll make an english version for yoy now) to remember it.
More - Mutation
Visitors - Varitation
Chose - Competition
Green - Favourable gene
Before - breeding
Teal - transfer favourable gene to the offspring
Very random acronym, but it covers all main evolution points (mutation in the gene leads to variation, there is competition and the more favourable gene will survive the environment, then there will be breeding and so the favourable gene moves to the offspring).
Looking at PMT ecology notes for AQA (link here
https://pmt.physicsandmathstutor.com/download/Biology/GCSE/Notes/AQA/7-Ecology/Detailed%20Notes.pdf) it can be a lot of 'common sense' if you understand the key terms. Looking at this unit a lot of it wasn't in my exam board's spec, but in geography we looked at similar things. Try and write a point or two for each environmental factor.
Biodiversity can have lush questions - main thing about biodiversity is it's the number of different species in an area, important for producing new foods and medicines, and so important to protect it. for the risks against it write a mindmap (so deforestation - 2 points, global warming - 2 points etc) but think about the real life scenario, if you cut the trees there is loss of habitat, the ground isn't as fertilised.
I'd make mindmaps for each key topic for ecology, then recall by trying to remake it (on whiteboard or paper), then compare. Try past questions on it then.
I'm not sure how helpful this was, if there's a specific thing you don't understand in the course I'll do my best to explain (probably get more luck with topic 6 for this)