Answer first, then the reasoning
Most FAQ entries build up to the answer: background, considerations, "it depends on several factors", and the actual answer at the end if at all. An extractive reader takes the first sentence or two. Put the answer there, then explain. If the honest answer is a range, give the range in that first sentence.
One question per entry
An entry that answers "how much does it cost and how long does it take" cannot be quoted for either question cleanly. Split it. Two short entries are quoted more often than one thorough one.
Use the question the customer asks
Not the internal phrasing. People ask "能不能保证排名" rather than "关于排名承诺的说明". The question text is part of the match; writing it in corporate register loses the match before the answer is even read.
What gets a page skipped
An answer that praises the company instead of answering. A question written so it can only be answered favourably. Numbers with no basis. Hedging so thorough that no claim survives - "每个项目情况不同，具体需要沟通" answers nothing and will simply be passed over for a source that committed to something.
Answer the uncomfortable ones
What you cannot do. Who you are a poor fit for. What goes wrong most often and what happens then. These are the entries that get quoted, because almost nobody publishes them and a model looking for a balanced answer has nowhere else to go.
Mark it up, and keep the two in step
FAQPage markup helps, but only when it matches the visible text exactly. Markup containing a cleaner answer than the page shows is a contradiction, and a contradiction costs more than the markup gains.