Often pages are included both in the category and its subcategory which is rarely a good thing. Remove the parent category from the page in this case.
Use HotCat (see ad on the top) when you need to fix one page.
Use StubSorter when you need to change stub templates.
Use Cat-a-lot when you need to move many pages at once to the subcategory.
Category:Free software once had over 400 pages! I went over each page and recategorized it by including a category like by open-source license used or programming language it was written in. Took me 2 days to finish the job, now this category contains only 6 pages. There are still many categories like this: Category:Overpopulated_categories
If there are pages with this typo, they will all be listed
Go to these pages and fix the typo
^"the the" insource:/the (\[\[[^\]\|]*\|The |\[\[The [^\]\|]*\]\])/ - this for capturing duplicates with internal link texts (currently over 600 duplications, you can help! Click here to start) Nevermind, just fixed all 600 pages with the help of AutoWikiBrowser, took only five hours.
Sometimes there are duplicate references (which have the same links or their links go to the same page).
In that case, add <ref name=(unique reference name - usually author or first words from title)> to the first reference, and then replace all other duplicate references with <ref name=(reference name)/>.
This is important: Wayback Machine often has saved versions of the page with various dates - before choosing, look at access-date= or at Retrieved: and choose date which is closest and has the page with relevant information.
add archived link to reference:
If reference used {{cite web}} template, add archive-url=(url from wayback machine), archive-date=(date of saved page) and url-status=dead.
If it is an external link, use {{webarchive |url=(wayback url) |title=...}} template.
Unfortunately, sometimes Wayback Machine doesn't have saved page.
In that case, add {{dead link|date=November 2024|fix-attempted=yes}} directly before </ref>.