Your words are not their words
Trades develop internal vocabulary. You say "domestic EICR"; the customer types "landlord electrical certificate". You say "aesthetic treatments"; they type "lip filler near me". Optimising for your vocabulary is optimising for nobody.
Four free sources of real phrasing
Your own enquiries: the exact words in emails and texts customers send you. This is the highest-quality source you will ever have, and you already own it.
Search autocomplete and the "people also ask" and "related searches" blocks — these are aggregated real queries.
Your Google Business Profile and Search Console reports, which show the queries that actually reached you.
Competitor page titles, read for vocabulary rather than copied — if three rivals all say "emergency" and you say "24-hour", that is worth knowing before you decide which is right for you.
Sort by intent, not volume
Group the phrases into: emergency, ready to buy, comparing, and researching. Build pages for the first two before you write a single blog post for the last one.
A phrase that ten people a month search and two of them hire you is worth more than one a thousand people search to read.