I would say- feed your passion! There are so many ways you can do this too. There are lots of interesting science bloggers on the internet that you can follow. Watching documentaries is a really great way of learning about different areas of science. One of my favourite programs is a BBC show called ‘Horizon’.
I also think it’s really important to nurture your creativity and imagination. A scientist’s job is to solve problems and answer questions that no-one knows the answer to. So you have to be creative to find the solutions to these problems.
One of the best things you can do, is talk to your friends about science. Talk about the things you have learnt, what you think about them and the questions you have about those topics. You can learn so much from each other!
As Emma said, looking for other sources of science outside of school lessons is a really great way to find out more. I loved reading popular science books, where you can learn about the sort of cutting edge science you wouldn’t normally encounter until the later years of an undergraduate degree. (Note this can also be a good thing when applying to do science at university as it is a way of showing your interest in the subject!)