Follow the lifecycle
Separate discovery, crawl, render, canonical selection and indexing. A problem at one stage can look like a content problem later.
Indexing problems often begin earlier than ranking. The first question is whether the intended page can be discovered, requested, rendered, canonicalised and selected for indexing.

Indexing: Bravaca visual explanation.
Each visual is selected for this page by meaning, not simply by keyword similarity.



Separate discovery, crawl, render, canonical selection and indexing. A problem at one stage can look like a content problem later.
Low-value utility, private, duplicate or incomplete pages may be better excluded. The aim is a useful index, not the largest possible one.
Search Console, server responses and rendered source are stronger evidence than assumptions based on what a browser appears to show.
Tell us what you are trying to improve. We will help define what should happen next.