If you think proofreading equals editing, then you're wrong! Editing is a lot more than just scrutinizing your manuscript for misspelled words or missing punctuation marks.
As a whole:
Edit only *after* you've written the *whole* piece. If you stop to edit after every paragraph or sentence, you will disrupt the flow of your thoughts.
It is better to take a break before starting to edit a long manuscript so you’ll have a fresh perspective.
Revise only *hard copy* especially if your manuscript is quite long. Revising from a monitor is confusing.
Verify the spelling of names, figures, dates, and addresses. These are the most murdered items in manuscripts!
Be sure of what you put between those quotation marks! Otherwise, rephrase the line and omit the quotation marks.
Did you follow the writer guidelines? e.g., number of words required, font/font size specified, spacing, margins...
Edit your content:
Be sure that you did not stray from your topic. Are your paragraphs coherent?
Did you fulfill your purpose for writing that piece? Is your entertainment feature article entertaining enough?
Did your personality sketch bring out your subject's unique and distinct qualities?
If necessary, did you provide enough supporting data (graphs, charts, figures) for your piece?
If applicable, did your article answer the 5 Ws and H? Who, what, why, were, when and how.
Edit for tightness:
Remove redundant and useless words.
What about diction? Did you use the right word to express what you mean?
For example, "He stared at her" is more intense than "He looked at her." "Devour" is not the same as "eat."
Did you vary the length of your sentences? Combining long with short sentences makes your article easier and more natural to read.
Did you check that the body of your article is longer than the introduction (lead)? Some writers get carried way. They focus on an effective lead to hook the readers but neglect the body of the article!
What about tone and style?
Does your work reflect your writing style or does it sound like a copied work?
Did you use the active voice? Are you consistent with the point of view you used?
Do your title and the words you used match the tone of your piece?