JH Scherck

To break this down in a step by step fashion: 1) use GSC to look at the last 28 days (or 90 if you have low numbers) of search data, select to view clicks, impressions, CTR, and ranking position.

2) Sort keywords by impressions and find a target keyword that ranks between ~4.5-15 and gets at least 2000 impressions a month and is product relevant or very high traffic

3) Click into the keyword, and then select "PAGES" in the submenu, (if there's multiple URLs, click the URL that's getting the lions share of the traffic).

4) Once the proper URL is selected, click the "QUERIES" tab in the submenu and delete the keyword filter above the graph in order to find that specific URL's top keywords, and sort those keywords by impressions

5) Now that you have your top keywords by impressions for the existing post, google the top 10-20 keywords with low CTR in positions ~4-15 that have a high number of impressions (ignoring anything that isn't relevant to the business).

5.1) noting what kinds of content is ranking above the fold, and the intent/use of those top ranking posts, as well as any featured snippets (definitions and ordered and unordered lists), and video + image results and people also ask boxes.

Note: if all the content that's ranking above the fold for a particular query is similar in intent to the existing post + keywords in the title tags of the top ranking content are also similar to the existing post, you can...

.. refresh the content to optimize for that particular low CTR/high impression keywords that matches the existing content's intent and primary topic. However, If the top ranking posts in Google for a particular keyword with low CTR and high impressions is all explicitly...

... about that keyword, and the top ranking posts have a different intent and primary topic/keywords then the existing post that's up for being refreshed, its likely that a new piece of content that targets that particular keyword will need to be created to rank above the fold.