Related keywords are words and phrases closely linked to your main keyword. There are many ways to find them. You can even just ask ChatGPT.

But here’s the thing: These keywords aren’t useful for optimizing content.

If more traffic is your goal, you need to find keywords that represent subtopics—not just any related ones.

Think of it like this: you improve a recipe by adding the right ingredients, not everything in your fridge!

Below are two methods for finding the right related keywords (including the one I used):

Content optimization tools look for keywords on other top-ranking pages but not yours. They usually then recommend adding these keywords to your content a certain number of times.

These tools can be useful if you take their recommendations with a pinch of salt, as some of them can lead you astray.

For example, this tool recommends that I add six mentions of the phrase “favorite features” to our keyword research guide.

Does that seem like an important related keyword to you? It certainly doesn’t to me!

Keyword gaps are when competitors rank for keywords you don’t. If you do this analysis at the page level, it’ll uncover related keywords—some of which will usually represent subtopics.

In the Organic Keywords report, hit the SERP dropdown next to the keyword to see the current top-ranking pages. Look for similar pages that are getting more traffic than yours and have fewer referring domains.

For example, our page ranks #10 for “local SEO,” has 909 referring domains, and gets an estimated 813 monthly visits:

All of these competing pages get more traffic with fewer backlinks:

Hit the check boxes next to your competitors, then click “Open In” and choose Content gap.

By default, this will show you keywords where one or more competitors rank in the top 10, but you don’t rank anywhere in the top 100.

I recommend changing this so it shows all keywords competitors rank for, even if you also rank for them. This is because you may still be able to better optimize for related keywords you already rank for.

I also recommend turning the “Main results only” filter on to exclude rankings in sitelinks and other SERP features:

This is where common sense comes into play. Your task is to scan the list for related keywords that could represent important subtopics.

For example, keywords like these aren’t particularly useful because they’re just different ways of searching for the main topic of local SEO:

But a related keyword like “what is local SEO” is useful because it represents a subtopic searchers are looking for:

Now you have a bunch of related keywords, what should you do with them?

Every competing page was getting significantly more traffic than us for this keyword (and ranking significantly higher). One page was even getting an estimated 457 more visits than ours per month:

People were also searching for this in a bunch of different ways:

My theory on why we weren’t performing well for this? Although we did have a definition on the page, it wasn’t great. It was also buried under a H3 with a lot of fluff to read before you get to it.

I tried to solve this by getting rid of the fluff, improving the definition (with a little help from ChatGPT), and moving it under a H2.

Result? The page jumped multiple positions for the keyword “what is local SEO” and a few other similar related keywords:

Once again, all competing pages were getting more traffic than ours from this keyword.

I feel like the issue here may be that there’s no mention of “strategy” in our post, whereas competitors mention it multiple times.

To solve this, I added a short section about local SEO strategy.

I also asked ChatGPT to add “strategy” to the definition of local SEO. (I’m probably clutching at straws with this one, but it reads nicely with the addition, so… why not?)

Result? The page jumped seven positions from the bottom of page two to page one for the related keyword:

Most of the competing pages were getting more traffic than us for this keyword—albeit not a lot.

However, I also noticed Google shows this keyword in the “things to know” section when you search for local SEO—so it seems pretty important.

I’d also imagine that anyone searching for local SEO wants to know how to do it.

Unfortunately, although our guide does show you how to do local SEO, it’s kind of buried in a bunch of uninspiring chapters. There’s no obvious “how to do it” subheading for readers (or Google) to skim, so you have to read between the lines to figure out the “how.”

In an attempt to solve this, I restructured the content into steps and put it under a new H2 titled “How to do local SEO”:

Result? Position #7 → #4

No. Nothing in SEO is guaranteed, and this is no different.

Each competing page got more traffic than ours from this keyword, with one getting an estimated 317 more monthly visits:

When I clustered the keywords by terms in Keywords Explorer, I also saw ~70 keywords containing the word “much” (this was around 19% of all keywords in the Content Gap report!):

These were all different ways of searching for how much SEO costs:

The issue here appears to be that although we do answer the question on the page, it’s quite buried. There’s no obvious subheading with the answer below it, making it hard for searchers (and possibly Google) to skim and find what they’re looking for:

To solve this, I added a H2 titled “How much does SEO cost?” and added a direct answer below.

Result? No change in rankings for the related keyword itself, but the page did win a few snippets for longer-tail variations thanks to the copy I added:

Nearly all competing pages were getting more traffic than us for this keyword, with one getting an estimated 72 monthly visits more than more us.

The term clustering report in Keywords Explorer also showed that people are searching for the monthly cost of SEO in different ways:

This is not the case for hourly or retainer pricing; there are virtually no searches for this.

I think we’re not ranking for this because we haven’t prioritized this information on the page. The first subheading is all about hourly pricing, which nobody cares about. Monthly pricing data is buried below that.

To fix this, I moved the data on monthly pricing further up the page and wrote a more descriptive subheading (“Monthly retainer pricing” →“Monthly retainer pricing: How much does SEO cost per month?”).

I also changed the key takeaways in the intro to focus more on monthly pricing, as this is clearly what people care about. Plus, I simplified it and made it more prominent so searchers can find the information they’re actually looking for faster.

Result? The page won the featured snippet for this related keyword and a few other variations:

I found this one in the term clustering report in Keywords Explorer, as 16 keywords contained the term “local.”

Upon further inspection, I realized these were all different ways of searching for the cost of local SEO services.

I think the problem here is although our post has some data on local SEO pricing, it doesn’t have the snappy figure searchers are likely looking for. Plus, even the information we did have was buried deep on the page.

So… I actually pulled new statistics from the data we collected for the post, then put them under a new H3 titled “How much does local SEO cost?”

Result? Small but notable improvements for this keyword and a few other variations:

I saw that one competing page was getting an estimated 105 more monthly organic visits than us from this term.

When clustering by terms in Keywords Explorer, I also saw a cluster of nine keywords containing the word “small.” These were all different ways of searching for small business SEO pricing:

Once again, the issue here is clear: the information people are looking for isn’t on the page. There’s not even a mention of small businesses.

This is good as it means the solution is simple: add an answer to the page. I did this and put it under a new H3 titled “How much does SEO cost for small businesses?”

Result? #15 → #5 for this related keyword, and notable improvements for a few other variations:

This related keyword probably isn’t that important, but I spotted it looking through the Content gap report and thought it’d be pretty easy to optimize for.

All I did was create a new H2 titled “SEO pricing models: a deeper breakdown of costs.” I then briefly explained the three common pricing models under this and re-jigged and nested the rest of the content from the page under there.

Result? #5 → #1:

Related keyword optimization isn’t about shoehorning a bunch of keyword variations into your content. Google is smart enough to know that things like “SEO” and “search engine optimization” mean the same thing.

Instead, look for keywords that represent subtopics and make sure you’re covering them well. This might involve adding a new section or reformatting an existing section for more clarity.

This is easy to do. It took me around 2-3 hours per page.