How do I improve my essay writing technique?

As you practice your technique, your essay writing will generally improve but to support this development you should consider structure, conciseness, use of evidence and purpose. 

I found it very useful to create a plan before writing essays for my A level English course. Planning ensures that you know what you want to write about and that you have a set structure to your essay. It will also help you keep track while writing the essay which will result in more consise arguments. I would also suggest that you locate your evidence before writing and integrate this into the plan for similar reasons. 

Finally, you should also think about the purpose of your essay. Consider what you want to deduce from the text/texts and what you want to express or reflect in your writing.