I got a 7 at GCSE and an A* at A level... It's quite different from the GCSE but I enjoyed it a lot more. My main tips would be
- actually read the texts. You'd be surprised the number of people who think it makes the same difference to read summaries or watch the films. Summaries and films can be great, but as well as rather than instead of reading the books.
- don't worry about the grade you get in your first essay. Before you write each essay that follows, reread the comments your teacher gave in your last one and specifically focus on that.
- go through on Google and find lots of nice interesting literary techniques and practice annotating texts, especially poetry with them. This will make any unseen annotation so much easier.
Have fun, I loved A level English lit!