I also studied french at uni, and I'm also a French and German tutor for GCSE and A level languages students.
With listening, my main tip is to do a lot. Switch between native-level and A2/beginner level listening extracts. Rather than aiming to understand everything, aim to pick out words that you know from the extracts. Over time, you'll get better and better at this and you'll be able to understand linger extracts. Listening to some native-level extracts will also help as it will make the GCSE-levwl extracts feel less fast and overwhelming. Also, if you're listening to things you're interested in, you're more likely to practice more often.
With reading, again, practice lots. But if it's hard then you can try annotating the texts. For example, underline the verbs, which tenses they're in and which nouns they apply to. This might also helping with your writing skills!
Something that will help with your language in general is just learning vocab. On some sites you can listen to how the words sound while you learn them, which can really help when it comes to listening as you've already heard them.