TLDR; you want to remove foreign debris before polishing or applying any force against against the screen, and you don't want to use a lot of force even in the polishing stage.
If you want to be extremely anal....The screen has an outer optical coating that is delicate. Harsh chemicals, skin oils, foreign particles, improper cleaning, and potentially excessive cleaning can all damage the coating. To be certain the coating is kept in tip-top condition, I like cleaning it in a few stages. If there is a lot of junk on the screen, first hit it with some compressed air or use a terry towel to 'swipe' horizontally to gently 'brush' the particles/junk off the screen without putting any pressure against the screen (you do this because if you just spray your towel down and start wiping, you may be grinding these foreign particles into the screen and scratching the crap out of it.) Then, spray/dampen your towel with a small amount cleaner or water, and wipe the screen with extremely light pressure to remove any additional particles the first stage missed and remove oils/stains. If the screen is extremely dirty, turn the towel to a clean portion frequently. Then, finally, using either a clean side of the towel or (preferably) a different towel entirely (that should always be clean), you can gently polish the screen with a slight amount of pressure to get it completely 100% streak free. I like to keep the towel I polish with in its own sealed bag and use it only for this purpose. (Some recommend omitting the last stage and using a 1:3 IPA to distilled water solution for AR-coated optics--I've used this solution when there was something on the screen that did not remove easily.)
After that, avoid touching the screen, and clean the topcase as needed to greatly reduce the frequency in the full screen cleaning and help avoid both screen damage and coating damage. You'll find that this almost eliminates oil buildup on the screen and that you rarely have to clean it beyond a quick light shot of occasional compressed air. Do not use any sort of keyboard cover.
Some may consider this overly anal and perhaps it is. But you wont find a single defect on my MacBook Pros, monitors/televisions, glasses, or telescopes even under an intense light.