With very rare exceptions, Court of Appeal hearings are open to the public. It is a good idea to watch an appeal hearing before your own; it will give you a better understanding of court procedure, and how you should best conduct your appeal. Weekly hearing lists for appeals and chambers applications are published on the Court of Appeal website.
The most important thing to remember about getting ready for a court hearing is that you need to be organized. It is a good idea to make notes about how you want to present the details about your case including, for example, the facts that you believe the decision-maker misunderstood, the law that you are relying on, the transcript paragraphs you will be referring to, and so on.
You may also want to talk with a lawyer about how to present and argue your appeal at the hearing. There are many ways to get pro bono (free) advice or help with your case.