One question per article
An article that answers three related questions is harder to retrieve accurately than three articles that each answer one — when a customer asks about shipping cost specifically, an article titled "Shipping, returns and exchanges" makes the assistant do extra work to isolate the relevant third, and it's more likely to quote a neighbouring paragraph that answers a question nobody asked.
This feels like it should create more articles to maintain, and it does — but each one is easier to keep accurate, because a change to the returns policy only touches the returns article, not a shared page that also covers two other topics.
Put the answer in the first two sentences
Retrieval tends to weight the opening of an article more heavily than content buried further down, so an article that opens with three sentences of context before it gets to the actual answer is handing the assistant a worse version of the article than the one a person would read top to bottom. Lead with the answer, then add the context and exceptions after it — a person skimming benefits from this too, not just retrieval.
State conditions explicitly, don't imply them
"Refunds are processed within 5 business days" and "refunds are processed within 5 business days, unless the order was paid by bank transfer" are different answers, and an article that states the general case without the exception will produce a confidently wrong answer for anyone the exception applies to. If an answer depends on a plan, a region, a payment method or a date, say so in the sentence that gives the answer — not in a caveat elsewhere on the page that the assistant might not retrieve alongside it.
Write the fix, not the story of finding it
Troubleshooting articles often read as a narrative: what was tried first, why that didn't work, what was tried next. That's a reasonable way to write for a person following along step by step, but it gives an assistant several plausible-looking but wrong answers to quote before it reaches the one that's actually correct. State the working fix directly, and if the failed attempts are worth documenting, put them after the fix, clearly marked as things that don't work — not before it.
Keep dated or conditional content out of your core articles
A seasonal promotion, a temporary policy change, or an announcement about a past event doesn't belong in the same article as your permanent policy — once it's outdated, it either needs to be manually removed or it sits there as a source of contradictory answers. If a source has to include this kind of content, keep it in clearly separate, clearly dated articles rather than editing it into an evergreen one and hoping to remember to revert it later.
Review what the assistant couldn't answer, not just what it got wrong
A wrong answer is a training signal you'll eventually see in a bad transcript. An unanswered question — one the assistant escalated because nothing in the knowledge base covered it — is a training signal that's easy to miss unless you go looking for it, and the resolution report is where it shows up. A recurring unanswered question is usually the single fastest knowledge-base fix available: write the missing article once, and every future instance of that question gets answered instead of escalated.