It will depend a bit on what topics your teachers pick. Generally, it is basically just GCSE with more in-depth content and longer questions. Once you know the content (the content isn't difficult, just quite a lot of it) and know how to answer the questions it is fairly easy.
The topics are:
Water and carbon cycles
either Hot desert systems and landscapes or Coastal systems and landscapes or Glacial systems and landscapes
either Hazards or Ecosystems under stress
Global systems and global governance
Changing places
either Contemporary urban environments or Population and the environment or Resource security
You also have a coursework assessment where you will carry out research on a topic. The topic has to be linked in some way to the topics that are taught. It is similar to a science report where you do background, method, results, analysis, conclusion, evaluation etv.