Here’s a link to some common English mistakes and how to fix them.
If you are not sure how to structure an essay, this might help. It allows you to put in your main ideas to get an organized outline, and then you can use the outline to write an essay. Of course, on your real exam, you will need to make your own on paper 🙂
Here is a link to some useful phrasal verbs.
This website has a lot of examples of everything, really. It’s not all worthy of a band 9, but there is some good information. This example is quite strong, although the use of paragraphs is not completely logical.
Here is a table with some useful vocabulary for describing trends. (Avoid “go up” and “go down” by using more academic words)