On the substance, your project must have a clear central argument (for example, Mondovino has an argument!) and demonstrate your understanding of important wine debates, conflicts of interest and battles over competing ideas of wine. You will all need good research and a strong, thorough bibliography, though the way it will be included will vary depending on the format. We can discuss details once you pick what you want to do.
Presentation of argument: Your project, whatever its form, should have a clear central argument and thesis and the project should be constructed to defend it.
Execution/presentation of ideas: An A level project will be something that looks close to ready for professional use, something that could actually be used in the real world. If you do a great job with it, maybe you can use your project as part of your portfolio later.
Quality and breadth of sources: Use a minimum of 20 sources (the more, the better informed you are). Pay close attention to the quality and relevance of your sources. You need to have enough substantial academic (i.e. books and full length academic articles) as well as short or long pieces you will find on good popular wine magazines, blogs. A general rule to follow may be a minimum of 8 academic sources PLUS as many relevant popular (blog/magazines/news) pieces you can find. There is a huge supply of popular writing on wine all over the internet, make sure you assess your sources appropriately. As far as academic materials go, you will be surprised to see the vast amount of academic research (both in journal and book form) available on all sorts of wine topics, and in many academic fields.