Revising
You can not always edit every single error in your work, otherwise it would take you an extremely long time which is what revising and editing are for. Revising is going over your work and checking if you have made any grammatical errors. Not just once but over and over again. You have to see think and remember who you are presenting to and make changes accordingly. Look at the language you have used. For example you will not write in same language if you were presenting to a preschooler as compared to if you are presenting to a eighth or ninth grade student. Make sure that your presentation is appropriate and is not about too much violence.
Editting
Editing once again is just going over your work over and over again but to correct any spelling errors. You should always not only edit and revise your work yourself but get at least 2 peers to do the same too. you should see of you have cited and quotations that you might have used. Check if you are following the correct paragraph or essay format. Don't only read the work in your mind because when you read it only in your mind you wont be able to point out as many mistakes as you would when you are mumble reading. Mumble reading is reading in a low voice. Mumble reading helps point out many mistakes you do not usually notice. Always remember to revise and edit your work over and over again because the more your edit the better result you will get.