9 proven on page SEO checklist for 2026 (backed by real studies)

There's no shortage of SEO advice online. The problem? Most of it is recycled opinion dressed up as fact.

This guide is different. Every recommendation below is backed by actual experiments, large-scale studies, or controlled A/B tests. No guesswork, no "best practices" that nobody has ever tested.

Whether you're optimizing your first website or refining an established one, these nine on-page SEO tactics have been proven to work.

1. Add external links to authoritative sources

Let's start with one of the most overlooked tactics: linking out to other websites.

Many business owners worry that external links "leak" authority or send visitors away. The data tells a different story.

The Reboot Online Experiment

SEO consultant Shai Aharony conducted a controlled experiment that settled this debate. He created 10 identical websites about a made-up compound called "Phylandocic" (a word with zero existing search results). Five sites included external links to authoritative sources, such as Oxford University. Five had no external links.

The result? After five months, 100% of sites with outgoing links ranked higher than those without them. The experiment was replicated in 2020 with identical results.

What to do: Add 2 to 3 relevant external links per page to high-quality, authoritative sources. Think industry bodies, research institutions, or well-regarded publications.

2. Build a strong internal linking structure

Internal links are one of the most powerful (and free) ranking tools you have. The evidence is compelling.

Cyrus Shepard's study of 23 million internal links across 1,800 websites found a clear relationship between internal links and organic traffic:

That's a 4x improvement simply by adding more internal links to your pages.

Even more interesting: pages with at least one exact match anchor text received 5x more traffic than those without.

SearchPilot's A/B test on Iceland Groceries showed a 25% uplift in organic traffic after improving the internal link structure between category pages.

What to do: Aim for 40 to 50 internal links per important page. Use descriptive anchor text that naturally includes your target keywords.

For WordPress users, check out our guide to WordPress internal linking for practical tips on implementation.

3. Optimize your title tags (but keep them short)

Title tags remain important, but there's a catch - Google rewrites them more often than you might think.

Ahrefs analyzed 953,276 pages and found Google rewrites title tags 33.4% of the time. Titles exceeding 60 characters are 57% more likely to be rewritten.

The Etsy engineering team ran randomized controlled experiments on millions of product pages and discovered that shorter title tags drove more visits. Their hypothesis: titles that closely match search queries perform better.

Title Tag Best Practices:

1. Keep titles under 60 characters (or 600 pixels)

2. Include your primary keyword near the beginning

3. Make them compelling for humans, not just search engines

4. Avoid keyword stuffing

What to do: Write concise, keyword-focused titles under 60 characters. If Google keeps rewriting yours, check what H1 you're using (Google uses it as a replacement 51% of the time).

Your URL structure matters too. See our guide to SEO friendly URLs for more optimization tips.

4. Create comprehensive content (quality over word count)

Here's something that might surprise you: Google's John Mueller has explicitly stated that word count is not a ranking factor.

So why do longer articles often rank better?

Backlinko's study of 912 million blog posts found that content over 3,000 words receives 77.2% more backlinks than articles under 1,000 words. It's not the length that helps. It's that comprehensive content naturally attracts more links.

HubSpot's analysis identified a sweet spot: posts between 2,100 and 2,400 words generate 287% more organic traffic than posts under 1,500 words.

The takeaway? Don't pad your content to hit a word count. Instead, cover your topic thoroughly and answer the questions your audience is actually asking.

What to do: Focus on comprehensiveness rather than hitting arbitrary word counts. Cover subtopics, answer related questions, and provide genuine value.

Need help structuring your content? Our SEO friendly blog formatting guide walks through the essentials.

5. Use header tags for structure (not just keywords)

Traditional SEO advice obsesses over H1 tags. The reality is more nuanced.

Neil Patel's controlled experiment tested different heading structures across multiple sites. His conclusion: "Headings don't have a big impact on rankings." The differences were statistically insignificant.

Google's John Mueller confirmed this: "You can use H1 tags as often as you want on a page. There's no limit. Your site is going to rank perfectly fine with no H1 tags or with five H1 tags."

However, headers still matter for:

• User experience and readability

• Helping Google understand your content structure

• Creating jump links and featured snippet opportunities

• Accessibility for screen readers

What to do: Use headers to create a logical structure that helps readers navigate your content. Include keywords where they fit naturally, but don't force them.

6. Improve your page speed and core web vitals

This is where we see some of the strongest experimental evidence.

The Deloitte and Google study analyzed 30.5 million user sessions and found that a 0.1 second speed improvement was delivered:

• 8.4% increase in conversion rate (retail sites)

• 9.2% increase in average order value

• 10.1% conversion increase for travel sites

For rankings specifically, SISTRIX's Core Web Vitals study found domains meeting all three metrics gained 3.7% visibility compared to the 2.7% average. That's a 37% relative advantage.

Quick Win: Check Your Core Web Vitals

Run your site through PageSpeed Insights and focus on these three metrics:

• LCP (Largest Contentful Paint): Under 2.5 seconds

• INP (Interaction to Next Paint): Under 200 milliseconds

• CLS (Cumulative Layout Shift): Under 0.1

What to do: Prioritize speed improvements that affect LCP first (usually images and server response time). Even small improvements deliver measurable results.

For a deeper dive, read our guide on how to improve Core Web Vitals and explore website speed optimization techniques.

7. Implement schema markup for better click-through rates

Let's be clear: schema markup won't directly improve your rankings. Google's John Mueller confirmed this in April 2025.

But the click-through rate benefits are substantial.

Milestone Research's study of 4.5 million queries found rich results achieve 58% CTR compared to 41% for standard results. The FAQ schema performs even better, achieving 87% CTR.

seoClarity's controlled test showed CTR increased from 1.02% to 2.22% after implementing FAQ schema. That's a 117% improvement.

Schema Types Worth Implementing:

• FAQ schema for informational pages

• Product schema for ecommerce

• LocalBusiness schema for local businesses

• Article schema for blog posts

• Review schema where applicable

What to do: Start with FAQ schema on your most important informational pages. Use Google's Structured Data Testing Tool to validate your markup.

Learn more about rich snippets and their benefits for your search visibility.

8. Keep your content fresh with regular updates

Google's Query Deserves Freshness algorithm rewards updated content, particularly for time sensitive topics.

HubSpot discovered something remarkable when they audited their blog: 76% of monthly views came from old posts, and 92% of leads came from content published months or years earlier.

When they systematically updated historical content:

• Organic search views increased by 106% per optimized post

• Monthly leads from optimized posts doubled

• One post saw a 240% increase in conversion rate

Siege Media's analysis found the average top-ranking page was last updated within 2 years. Their recommendation: refresh important content every 9 to 12 months.

What to do: Audit your existing content quarterly. Update statistics, refresh examples, and add new information where relevant. Don't just change the date without making meaningful improvements.

Not sure where to start? Our content audit guide explains how to identify which pages need attention first.

9. Optimize images for speed

Here's a finding that challenges conventional wisdom: SearchPilot's A/B test on adding keyword-rich alt text to product images found no detectable impact on organic traffic.

Alt text is confirmed as a ranking factor only for Google Image Search, not regular web results. For most businesses, the bigger opportunity is using image optimization to improve page speed.

Image Optimization Priorities:

1. Compress images (aim for under 100KB where possible)

2. Use modern formats like WebP (30% smaller than JPEG)

3. Implement lazy loading for images below the fold

4. Specify image dimensions to prevent layout shift

5. Add descriptive alt text for accessibility (and Image Search)

What to do: Focus on image compression and modern formats first. Add alt text for accessibility and to support Image Search, but don't expect it to move the needle for regular rankings.

For the full picture, read our guide on how to optimize your website's images and understand why alt text matters for accessibility.

Your on-page SEO action plan

The beauty of evidence-based SEO is that you can prioritize with confidence. Here's a summary of all nine tactics with their supporting evidence:

Based on the research, here's where to focus your efforts:

High Impact (Strong Experimental Evidence):

• Internal linking structure

• Page speed and Core Web Vitals

• Schema markup for CTR

• Content freshness updates

Medium Impact (Correlation Evidence):

• Title tag optimization

• Content comprehensiveness

• External links to authorities

Lower Impact (Weaker Than Expected):

• Header tag structure

• Alt text for web rankings

• Keyword density

The key is to stop guessing and start testing. These studies show what works at scale, but every website is different. Use this checklist as your starting point, then measure what moves the needle for your specific situation.