"Technical SEO" sounds like something only a developer should worry about, but most of it is actually straightforward once you know what you're looking for. At its core, it's about making sure Google can do three things properly: find your pages, understand what they're about, and load them quickly enough that visitors stick around. When one of those three breaks down, rankings suffer, often without any obvious warning sign.
Crawlability: can Google even find your pages?
Before a page can rank, Google has to discover it, follow a link to it, or find it in your sitemap. Pages that are technically online but poorly linked from the rest of your site are known as orphaned pages, and they're far more common than most site owners realise. A robots.txt file that accidentally blocks a whole section of the site is another classic cause, usually left over from when a site was in development and never updated before launch.
Your XML sitemap matters here too. It should list every page you actually want indexed, and nothing you don't. A sitemap that's out of date, missing new pages or still listing ones that were deleted months ago, sends mixed signals about what's actually worth crawling.
Indexation: is Google choosing to skip your pages?
Being crawlable doesn't guarantee being indexed. Google can visit a page and still decide not to include it in search results, usually because the page looks thin, duplicated, or not worth showing. Duplicate content is one of the most common causes, the same or very similar content living at more than one URL, which splits ranking signal between them instead of concentrating it on one strong page.
Canonical tags exist to solve exactly this problem, telling Google which version of a page is the "real" one. When they're missing, incorrectly set, or pointing at the wrong page entirely, Google is left to guess, and it doesn't always guess in your favour.
Quick check: search site:yourdomain.com in Google and compare the number of results to how many pages you think your site actually has. A big mismatch either way is worth investigating.
Speed and Core Web Vitals
Google measures three things under the banner of Core Web Vitals: how long the biggest visible element takes to load, how quickly the page responds to the first interaction, and how much the layout shifts around while everything loads in. All three affect rankings, and all three affect whether a visitor sticks around long enough to actually read your content or fill in a form.
The most common causes are unoptimised images, too many render blocking scripts loading before anything useful appears on screen, and fonts or adverts that shift content around as they load. None of these are usually difficult to fix once identified, the hard part is knowing which ones are actually affecting your specific site.
How to actually find these issues
Google Search Console is the best free starting point. The Coverage report shows exactly which pages are indexed, excluded, or causing errors, and the Core Web Vitals report shows real, measured data from actual visitors rather than a lab test. Beyond that, a proper crawl of the site using a tool built for the job will surface broken links, missing canonicals, redirect chains and duplicate content that are easy to miss by browsing the site normally.
What trips people up isn't usually finding issues, tools are good at generating long lists of them. It's knowing which ones on that list are actually worth fixing first, and which are minor enough to leave for now.
The bottom line
Technical SEO isn't about chasing a perfect score on every tool going, it's about clearing the specific blockers stopping your site from being crawled, indexed and loaded properly. Fix those, and the content and links you've already built have a genuine chance to perform the way they should.