Once you have a rough draft for your essay, it's time to start editing. When reviewing your essay, you need to be looking at a few different elements:
Editing for content - Are you providing important information and not wasting space with unnecessary details and words? Are you answering all of the essential questions and not leaving anything unanswered?
Editing for grammar - Your essay should be easy to read, and errors in spelling, punctuation, and grammar should not be included in your final draft. While this isn't an essay for literature class, it is probably the most important 5,000 characters you will ever write. You don't want poor grammar and careless mistakes to distract your reader.
Editing for flow - Is your essay easy to read? Does it make sense? The experiences you discuss in your essay should make sense chronologically and be easy to follow. A confusing essay is one of the worst kinds. It makes it difficult to focus on the content when I'm just trying to figure out how everything fits together.
While you will obviously want to edit your essay yourself, you need to have others read it as well. A family member or friend's opinion is great, and they may be able to help you with grammar, but that isn't the most subjective option. Since you're writing an essay to try to get into physician assistant school, you need a PA to read your essay. This can be someone you have shadowed or worked with, or you may consider a revision/editing service. These services will NOT write your essay for you, and I would discourage you from pursuing any avenue that offers to do this. I work with myPAresource because they only use PAs, many of which have served on admissions panels, and the feedback you receive is honest and extremely helpful. If you decide to use the services over at myPAresource, make sure to use the code "thePAPlatform" for a discount!
To end the discussion on editing, I have to give you a caution. Please do NOT have someone random on the internet that you talk to in a forum or group edit your essay, especially if it is a fellow applicant. You can't know someone else's motives, and you don't want to take the chance of someone else plagiarizing part of your essay or stealing your ideas. Make sure anyone who is reading your essay is someone that you know and trust, or a secure service.