Hi, I studied Eduqas A Level French and came out with a high grade, so hopefully some of this will be useful! To build up your listening skills, I'd recommend listening to French podcasts, especially news channels as they cover recent topics and give a French viewpoint on a subject (which can be helpful to use in your speaking exam too). For example, there's a podcast called L'Heure du Monde which you can listen to on Spotify, and they release 20 minute episodes every day. Of course, using past papers is probably the most useful technique for improving listening skills and also getting an idea of the standard required by your exam board. What I found when I was revising is that I had already done most of the past papers for my exam board, so if you're starting revision now I'd suggest practicing by using past papers from different exam boards so you have some AQA ones left to do nearer the time of sitting your exams.
For the speaking, I also struggled with expressing myself more comprehensively and not running out of ideas, but I went through the specification and made mind maps on each topic (such as facts/figures/dates/some statistics that are specifically linked to France or other French-speaking countries) to not only feel more prepared to deal with the photo card but also to demonstrate to the examiner that I had a good understanding of the course content. As you're self studying (which is super impressive!), I'd also recommend finding a group of other A Level French students sitting their exams next year that you can practice speaking with. If you struggle with speaking confidently, arranging regular speaking sessions with a group of students at the same level as you can be a great way to work on your skills, especially if you practice with photo cards from previous exams (there are tons online).
I hope this is helpful for you! All the best with your exams