For my mocks, what has really helped is:
-bullet point plan before you start the essay. Each point could be a quote, a writer's intention, a technique etc, nothing too detailed
-context!
-make inferations and suggest the effect
-use connotations and links (eg. "This word connotates ... which could link to when ... happens which makes the reader/audience feel ... way")
-learn how to recognise and name techniques, structures, sentence forms etc
-use LEAR structure rather than PEE (google it)
-write why you think the author did this/used this technique/structure etc
-if you're really stuck, analyse in depth a single word which really backs up your point!
Hope this helps