Overusing adverbs (basically, essentially, actually) means that your verbs are not strong enough on their own. Wordy phrases and fragments slow down your narrative. Pedantic words like “myriad” and “plethora” should only be used if you know what they mean - otherwise you come across as someone disingenuous who used athesaurus to sound smarter (something admissions officers can easily see through.)

Inspired by Karyn, here are a few more things I would add to your admissions essay checklist for before you submit: