10 SEO Mistakes That Are Killing Your Website

In this guide, we'll break down the 10 most damaging SEO errors we see as an SEO agency working with businesses across Australia — and give you clear, actionable fixes for each one.

Thin content is the single biggest SEO killer in 2026. Google's Helpful Content system now actively demotes sites with pages that don't demonstrate genuine expertise, experience, authority, and trustworthiness (E-E-A-T). A page with 200 words of generic filler isn't just unhelpful — it drags your entire domain down.

The fix: Audit your site for thin pages using Screaming Frog or Sitebulb. Any page under 500 words that isn't serving a clear user intent should be expanded, consolidated into a more authoritative page, or removed entirely. Focus on creating comprehensive content that genuinely answers the searcher's question better than anyone else. Learn more about keyword-driven content optimisation to get this right.

Google confirmed Core Web Vitals as a ranking signal, and in 2026 the bar is higher than ever. If your Largest Contentful Paint (LCP) exceeds 2.5 seconds, your Interaction to Next Paint (INP) is sluggish, or your Cumulative Layout Shift (CLS) causes visual instability, you're haemorrhaging rankings.

The fix: Run your site through Google PageSpeed Insights and Web Vitals reports in Search Console. Common quick wins include compressing images to WebP/AVIF format, implementing lazy loading, deferring non-critical JavaScript, and using a CDN. If your site runs on WordPress, regular WordPress maintenance is essential for keeping performance optimised. For businesses needing a ground-up rebuild, our website development team can build a speed-first architecture.

Google now uses the mobile version of your site as the primary version for indexing and ranking — full stop. Over 65% of all searches happen on mobile devices. If your mobile experience is clunky, slow, or missing content that appears on desktop, you're invisible to the majority of searchers.

The fix: Test every key page with Google's Mobile-Friendly Test and manually browse your site on multiple devices. Ensure text is readable without zooming, buttons are easily tappable, and no content is hidden behind tabs or accordions that Google can't crawl. Responsive design isn't optional — it's the baseline.

Backlinks remain one of Google's top three ranking factors. A site with thin or no backlinks signals to search engines that nobody trusts or references your content. But the game has changed — quality overwhelmingly beats quantity. One link from a respected industry publication outweighs a hundred from low-quality directories.

The fix: Build links through genuine digital PR, guest contributions on relevant industry sites, partnerships, and creating link-worthy resources like original research or comprehensive guides. Avoid link farms, PBNs, and paid link schemes — Google's SpamBrain AI is extremely effective at detecting and penalising these in 2026.

If you serve customers in a specific area but haven't optimised for local SEO, you're handing business to competitors who have. Nearly 46% of all Google searches have local intent, and "near me" searches continue to grow year on year.

The fix: Claim and fully optimise your Google Business Profile, ensure NAP (name, address, phone) consistency across all directories, build local citations, and create location-specific landing pages. We've written a detailed guide on local SEO dos and don'ts that covers this in depth. You can also check our breakdown of 10 common local SEO errors for specific fixes.

Duplicate content confuses search engines about which page to rank, dilutes link equity, and can result in the wrong page — or no page — appearing in results. Common culprits include product pages with near-identical descriptions, printer-friendly page versions, and HTTP/HTTPS or www/non-www duplicates.

The fix: Use canonical tags to point duplicate pages to your preferred version. Implement proper 301 redirects for URL variations. Write unique meta titles and descriptions for every page. Use Screaming Frog to identify duplicates systematically.

Ranking for a keyword means nothing if your page doesn't match what the searcher actually wants. Google has become incredibly sophisticated at understanding intent — informational, navigational, commercial, or transactional. If someone searches "best CRM software" and lands on a page trying to immediately sell them one product, they'll bounce, and Google will notice.

The fix: Before creating any page, search your target keyword and analyse the top 10 results. What format are they? What questions do they answer? What depth do they go to? Match the intent. If the top results are comparison guides, don't publish a sales page. If they're how-to articles, don't publish a product listing.

If Google can't crawl your site efficiently, it can't rank your pages. Orphan pages (pages with no internal links pointing to them), overly deep navigation structures, and broken internal links all hurt crawlability and distribute page authority poorly.

The fix: Create a logical site hierarchy where every important page is reachable within 3 clicks from the homepage. Use contextual internal links within your content to connect related pages. Implement breadcrumb navigation. Regularly audit for broken links using tools like Ahrefs or Screaming Frog.

Your title tags and meta descriptions are your first impression in search results. Generic, keyword-stuffed, or missing meta data means lower click-through rates — which directly impacts rankings. Meanwhile, missing structured data (schema markup) means you're invisible to rich results, featured snippets, and AI Overviews.

The fix: Write unique, compelling title tags (under 60 characters) and meta descriptions (under 155 characters) for every page. Implement relevant schema markup — LocalBusiness, FAQ, HowTo, Article — to help Google understand and feature your content. Our guide on optimising for Google's SGE covers how structured data plays into AI search results.

The biggest mistake businesses make in 2026 is treating SEO as if it's still 2020. Google's AI Overviews, ChatGPT search, Perplexity, and other AI answer engines are fundamentally changing how people discover businesses. If your content isn't structured, authoritative, and comprehensive enough for AI systems to cite and recommend, you're losing an entirely new traffic channel.

The fix: Create content that directly answers questions with clear, well-structured information. Use FAQ sections, table-of-contents formatting, and authoritative citations. Build your brand's online presence across multiple platforms so AI systems encounter and trust your brand. Read our deep dive on AI and ChatGPT trends in digital marketing for a full strategy breakdown.

SEO mistakes compound. Each one on its own might cost you a few positions, but stack several together and you're looking at a traffic decline that's hard to recover from. The good news? Every one of these mistakes is fixable. Start with a comprehensive audit, prioritise the highest-impact fixes first, and build a culture of ongoing optimisation.