How to Sharpen Lawn Mower Blades

I’d like an article explaining how to sharpen lawn mower blades. I see it starting with a short piece on how to tell if your blades are becoming dull and the effect of having lawn mower blades that aren’t sharp. Then the main part of the article I would want to be a step-by-step guide to sharpening lawn mower blades with a list of items you need to sharpen them and how to do it. Maybe it could end with a look at how to determine if you need to replace the blade completely. I’d like the article to be friendly, breezy and relaxed in tone.