How to improve my maths grades/ skills?

Hey I understand ur situation, I've been there many years ago and finally found my way out...
From 50s I've now come up to 95+ which I think is great. I'm not boasting, but I mean is if an idiot like me could do it you can too!!!
This is a long message, and read it carefully.
Maths is like mayhem or even worse, but the moment you understand what math actually is you'll love it. If you want to improve;
First build a solid foundation - which means solidify the theories and know how it comes from. For example if your talking about differentiation you must know that it is determining how another variable changes when one changes, and after solidfied all these theories you must proceed to the next step...
Practice. Begin with relatively easy sums, like differentiation simple equations and gradually increase the difficulty, begin kinematics, the best way to seek help for a great teacher or a super bright, non-arrogant student.
Practice harder. After you've done try solving more complex problems, for example if you trying Edexcel iGCSE Maths A try doing Edexcel iGCSE Maths B, if you are doing edexcel iGCSE Math B try FPM (but be careful, you won't be able to do most sums because it contains alot of A/L theories, but you can try other examboards like Cambridge Paper 4, the sums are superb), if you trying FPM try A/L. But all this must be done once you've fully completed above steps.
Mixed papers, when you do one theory at a time you excel, so find difficult mixed papers and do them. I'll often recommend Cambridge Paper 4.
At the end close to your exams, once again look and all the theories and test if you can remember them or if you can derive them (if its possible and within the syllabus bounds). I mean like you can't prove the equation for differentiation, its needs FPM knowledge and a bit on A/L knowledge, but most of the circle theorems can be proven.
The most important part is the 1st step, it might be super difficult and boring, but believe me if you can do that, you'll probably get better exponentially. This is how I became better.
There is quite a lot of work to do and I won't hide it, because if I don't tell you this you'll fall behind thinking its too hard...
Anyway good luck pal... Get your 9! You deserve it! If you work hard and smart you can do this! Don't over rely on my method, maybe it might not suite you, if not try different ways till I fits perfectly for ya!
GOOD LUCK!!!

Improving your math skills is totally doable, and it’s great that you want to get better. Since you’re already at a G6 level, the key is to figure out where you’re struggling the most and then practice those areas. A good way to start is by looking at your past tests or homework. What questions did you get wrong? Those are probably the topics you should focus on first.
Try breaking it down like this: Spend some time each day reviewing the basics (like fractions, decimals, or whatever feels shaky) and then slowly tackle harder stuff. Apps like DoodleMaths, SpiralLearning (https://spirallearning.pages.dev/app) are great for quick fixes on foundational skills, and Khan Academy is super helpful for brushing up on specific topics with videos and practice problems.
Also, don’t just memorize steps. Try to really understand why things work. If you’re stuck, ask your teacher, a friend, or even watch a YouTube explanation. And practice, practice, practice! The more problems you do, the more confident you’ll get. You got this! 💪