Part 1
Writing the line that gets the click
The description does not move your position. It decides whether a person picks you out of a list where everyone is technically correct. The strongest ones name the specific thing the reader gets and admit a limit, because a line that promises everything reads like every other line on the page.
Write it as the answer to why should I open this one rather than the one above it.
Part 2
SERP features and who they take from
Featured snippets, people also ask, image packs, local packs and shopping units sit above or between the ordinary results and take attention from them. Being first in a list that starts halfway down the screen is worth less than it used to be, and that is a positioning problem rather than a ranking one.
Look at the actual result page for your phrase before deciding what position is worth chasing.
Part 3
Why position three sometimes beats one
A result whose title matches the exact question can outperform the one above it, because people scan for their own words rather than reading in order. Position matters, and match matters too, and only one of the two is under your direct control this week.
When you cannot move up, move closer to the wording people actually use.
Part 4
Measuring without lying to yourself
Position tracking measures the search engine. Clicks and impressions measure people. Sessions measure your analytics setup. They disagree, and the disagreement is normal rather than a fault. Pick the one that maps to the decision you are making and stop quoting whichever number is highest that week.
Write down which number you will judge the change by before you make the change.