I practice AWA by answering prompts from the ETS website and then reading through my essay for structure and sentence complexity. I like to look at prep book essay structure and compare how my essays are structured. For example, I noticed that tutors will often rephrase the prompt in their first few sentences and transition into their thesis statement, which is something I hadn't been doing.
I think grammarly is a great resource. If I were you, I would focus on my grammar and punctuation. You have many run-on sentences, which can be easily fixed by making sure that each sentence has a singular point. Your writing will improve greatly with some work in punctuation and sentence structure. Khan Academy has videos on sentence structure if videos are helpful to you.