Put plainly, get the facts to agree, and comparison sites will do the rest without being asked.
Confirm what a competitor in a crowded metro market has claimed before deciding where to submit.
Treat the primary category as a single source of truth, not as a field to be improvised per site.
Confirm by phone or postcode lookup, not by memory. The gain is seldom dramatic on any single day; it surfaces as faster indexing over a quarter. Left alone, silent listing decay spreads to sources the business never submitted to.