Administrivia: Edit Reasons and Why You Should Use Them
There is a small box◊ under each page in editing view that allows you to leave an (optional) edit reason. While edit reasons are indeed optional, they are often a very good idea, for both adding information and removing it.
When adding information, leaving an edit reason is often a good idea for the following reasons:
It clarifies why you chose to add the information, and what your rationale is for posting it. Of course, some edits adding information are self-evident (e.g. examples) and therefore don't need an edit reason. Others (especially those making major changes to a page's information via addition, adding recent information or information not widely known) are far less self-evident, and an edit reason is therefore a good idea.
While edit reasons are not and should not be citations, they can be used to verify content as being something legitimately added in good faith rather than vandalism or trolling. This is very important, especially when changing a page to reflect something like a creator's death, or a trope generally seen to be one of Sturgeon's Tropes or having Unfortunate Implications in a work, where a vandal edit may very well be a problem.
It points to exactly what you've changed on the page as a quick reference, especially if it is a major change. Or even if it's a minor change—take pity on the poor troper who scours a paragraph looking for what you edited and not realizing you simply added a comma in the center of it.
When removing information, leaving an edit reason is even more vital because of the following reasons:
It says exactly why you've removed the information.
It helps people to understand why the information was undesired in the first place. As in, if you are going so far as to remove information someone has taken time to share, it's only polite to tell them why. In the cases of things such as natter and NSFW links, some new users may be genuinely unaware that Conversation in the Main Page or linking to a Gelbooru pool is unwelcome and unwanted. Leaving a polite edit reason linking to the page on the policy related to the removed material is a courtesy that may help them to become a productive editor.
It prevents the information from being re-added, at least without a discussion. A removal without a reason (or with a rude or unrelated one) is an invitation to begin Edit Warring, especially for a newbie who doesn't understand how things work around here.
It shows the removal to be in good faith, rather than a case of page blanking, vandalism, or trolling.
It documents what has been removed.
When removing information, it's also a good idea to leave an edit reason for each removal.
If the cleanup is something where all removals have the same reason, such as cleaning natter and the only edits are the natter removals, it's probably not necessary to leave a reason for each.
On the other hand, if your edit reason is "natter", but you've taken out one line of natter while you've also taken out a huge chunk of the main description of the work, several tropes that seemed to apply, and cut out non-lewd trope descriptions to leave several tropes with a near Zero-Context Example, your one reason edit may be seen as an excuse for nonconstructive editing.
A null edit is the process of opening the edit page screen, then immediately saving it without making any changes. There are a few reasons why you might make one.
To leave a reason relating to a previous edit. This will only show up on the page history, not the actual page. These can be used to do things like explain someone else's edit (or your own, if you forgot to leave one on the last edit you made), e.g. if they deleted YMMV items off a main work page without moving them or saying they were going to, you could leave an edit reason noting that you had ensured they were all moved.
Edit reasons like this can also be for stuff relating to Edit Wars. If there's an example that's been removed a couple times in quick succession, an edit reason like "Taking it to the discussion page" will encourage tropers to go there rather than continuing the war. It also tells anybody with the page on their watchlist that more is happening, whilst not continuing the edit war. The example can then be discussed in depth.
Sometimes, you need a null edit to get indexing to kick in. This can happen if a page is namespaced on an index, but isn't moved there yet, and the index bar doesn't show up at the bottom of that page. A null edit to the index page fixes this. An edit reason like "indexing trouble" is fine, though you don't really need one at all.
Similarly to the above, due to the custom-title system, if a page is cut, all pages with the same title in all namespaces will all be displayed as a Red Link. Example If Laconic.Tropes Are Flexible were cut, then Administrivia.Tropes Are Flexible would display as a red link, though the page would still exist. Null editing such a page will correct this problem.
Coolness and Rudeness
Please be cool when you edit.
Being cool when you edit means to keep your edit reasons somewhat concise (if you can't sum up your edit reason in 50 words or less, you should probably link the discussion page instead of using the edit reason box for it, and sermonizing in edit reasons is incredibly uncool).
It also means being clear in your edit reason - see the point above on removing material. Sometimes a simple "added event xyx" can be cool if you're adding information, for example, or if you're removing a bad link, "Links to gelbooru pools violate policy" is better than "Ewwwww I don't want to see that shit!"
Keep your mood in mind. If you're having a bad day or in a bad mood in the first place, it's probably a good idea not to go editing. TV Tropes is not your job (even though it can feel like it), so you're not obligated to work on it no matter your mood. If you find you're finding stupidity that needs to be removed wherever you go and it's irritating you more and more, taking a break is probably a good idea. Likewise, don't use this kind of editing as a way of getting your stress out.
Rudeness is not cool
A rude edit reason includes, but is not limited to, any of the following:
A personal attack on an editor, e.g. "Report Siht is a basement dwellingotaku," or a removal with "Comments such as this are the reason why all people like you suck."
An attack on the quality of previous editors' contributions, e.g. "Nobody cares" or "Who gives a fuck?"
Hate speech, e.g. "You're all [homophobic slur]," or "[racial slur]s"
Trying to intentionally bait for an Edit War, e.g. "Put that back I dare you"
Gratuitous swearing not on an article like Cluster F-Bomb. If your edit reason contains "fuck", it will be blanked.
Threats, e.g. "I have removed your information and am contacting my lawyer," or "Say that to my 357 Magnum, asshole"
"Defending" a page from editors you don't want there, e.g. "This is my page, don't edit it" or "This page is about Uber Manly Testosterone Poisoning Combat: USMC BAMF, we don't want you saying that about Steele and Stone!" This is especially rude because we welcome all constructive editors and any page may be edited by any person as long as it is not locked.