Search engines do not publish a score called topical authority, but the idea describes something readers feel. Some sites clearly know a subject well. Others seem to dabble.
Choose a subject you can sustain
Pick an area where you can publish accurate, useful material for months. Narrow it enough to cover properly, such as technical SEO for small publishers, not "marketing".
Map the questions. List what a newcomer needs to learn, what an intermediate reader gets stuck on and what advanced readers argue about. Use Search Console queries, forum threads and reader messages. Group questions into themes.
Cover the basics before the edge cases
Authority is built on dependable fundamentals. Write the clear explainer, the checklist and the troubleshooting guide before the niche article.
Be accurate and current. One wrong claim damages trust more than many correct ones build it. Verify facts, cite primary sources and update pages when things change.
Link related articles
Link related articles to each other with descriptive text. Create category pages that introduce each theme and point to the best articles.
Avoid dilution. Articles far outside your focus can blur what the site is about. If you want to cover a new area, build it as a deliberate second theme.
Being patient
Building a reputation in a subject takes months or years. Do not expect immediate results from a few articles. Measure steady growth in impressions and the breadth of queries, and keep publishing carefully. Sites that stay focused and accurate usually outlast those that chase every trend.
A simple coverage map
Make a table with three columns: beginner questions, intermediate problems and advanced topics. Fill in the questions for your subject and mark each one as covered, outdated or missing. Fix outdated items before adding new ones. This map shows where the site is strong and where it leaves readers without help.
Repeat the exercise twice a year, since readers' questions change.
Signals that readers notice
People judge authority by clear authorship, honest sourcing, quick corrections, consistent quality and the absence of hype. A site that is open about its limits and keeps its pages current earns repeat visits. Those are slow signals, but they are the ones that last.
Measure progress sensibly. Look at the number of queries you appear for in the topic, clicks to the topic pages, and links or mentions from others. Progress is slow and uneven, which is normal.