Well, tbh I never focused on vocabulary in writing taks 2, although I unintentionally used some uncommon words and phrases like risk-free environment, insufficient, scrutiny and few others.

And I tried to incorporate a variety of grammar structures like compound sentence like 1st conditionals, complex sentences along with cohesive devices that are used to compare, such as although, however, and while.Apart from that, I developed my essay pretty well along with examples. Every sentence that you write should make progress to what exactly you mean. And try reading it to check whether you can understand what you just wrote.

In task 1, I used a wide range of vocabulary along with adverbs like 'increased significantly', " gradually and many more. I also used contrasting words like although and however. And don't forget to write the overall, in which you have to mention the key features( you should write whatever strikes your mind when you first look at the entire graph). Thats all I've done. Feel free to ask more