Original post by mdnvmprSophisticated vocabulary comes from reading a wider range of more challenging texts, then searching the words that you do not understand and making a note of them, and trying to include them in your writing. There's no quick easy way to do it, it comes over time with practise.
Some things I would recommend you to do when writing paragraphs:
Integrate quotations - this is where you quote words and phrases as part of a sentence rather than saying 'This is shown in the wuote/line...' this makes your writing much more concise and saves you time but also looks much better and will allow you to convey your point more effectively most of the time.
PETER paragraphs (point, evidence, technique, effect on reader) are good alternatives to PEE, as this structure is more detailed and reminds you to focus also on the EFFECT on the reader, which is very important in any english analysis, and something which many people forget to write about.
Another way to come across as intellegent is using subject terminology. Again, many people miss out on this, and it will show that you can identify techniques and help to get your marks up. 'Adjective' sounds much more sophisticated than 'word'.
Of course vocabulary will always will useful but is not something that you can really do overnight, but over a longer period of time.