Improving the on-page SEO score of your website is important because search engines put a certain weight on how properly organized a webpage is. Your content has to be good but then, it should also look neat and feel good to the eyes. You can't expect a good user experience on a page, which has all the words piled one after another, without any headings or section break. Using header tags, you can tell users and search engines about the different sections of content and what a particular section is all about. It is important to note that you want to get ranked for the long tail of search and header tags play a very important role, when you are considering ranking for varied keywords on a subject.
Above all, header tags contribute towards good user experience. Remember - What's good for the user is also good for the search engines.
Don't Use CSS or Style Elements for Marking Section HeadersA fundamental mistake most webmasters commit is that they simply increase or decrease the font size of a text using CSS or other style techniques and think that they have correctly implemented the section headers. In fact, this is a completely wrong way and you should abide by the following HTML markup for headers
<h1> Your Main Heading Of The Page Goes Here</h1>
<h2> This is the second Header tag which should come after the h1 tag in the HTML source</h2>
<h3> This is the third Header tag which should come after the h2 tag in the HTML source</h3>
You just cant increase the font size of a sentence and say "Hey, this is a header tag". You have to use the above markup or search engines won't consider that phrase to be a section break or the headline of a different section on the same given page.
Follow the Hierarchical Structure
This is not a hard and fast rule but it is strongly advised that you maintain the following hierarchical structure of header tags within any page of your site
Points to note:
- Do not use multiple H1 tags on a page. It won't hurt but on rare occasions, search engines might consider this as an act of keyword spamming. Besides that, it won't look good to human eyes either.
- Multiple H2, H3 and H4 tags on a page are allowed and considered a proper practice.
- Never overdo. Do not add a whole bunch of header tags on a page thinking that it might improve the on page seo score.
- Follow the hierarchical structure. If you want to use three H3 tags, be sure to include them within an H2 tag first. Like I said, it won't hurt if you skip the H2 completely and use all H3's but it is a good practice to maintain the seniority level of each header tag and include the juniors in nested levels.
The Structure of Your Website's Homepage
If your website is a blog and you're showing a list of recent posts on the front page, I would use all H2's for post titles and won't use the H1 tag at all. My explanation here is that more than one H1 tag in any page might look bad for users who have turned off CSS in their browsers.
If your website is not a blog and it has fewer sections (3-4), it perfectly makes sense to use the H1 tag for your main tagline. The H1 tag has more weight than H2's, so it definitely makes sense to use an H1 tag to describe what your website is all about.
On the other hand, if you use 15-20 H1's on the homepage of a blog, guess what happens? The value of each H1 is diluted to a great level as search engines see a group of H1 tags which are not very closely related. Hence the usage of H2 tags on the homepage for post titles.
The Structure of Your Website's Article Pages, Single Post pages
The single post pages or article pages on your site have a clear focus.
Hence, always use an H1 for the main heading and use H2's for subheadings. You can multiple H2 tags for different sections of the content and at the same time use H3 tags for further organization. Limit until H3 because H4, H5, and H6 tags do not have much weight as far as SEO is concerned. On my websites, I never use H4, H5, and H6 tags within the content section, these tags are reserved for labelling sidebar content, widgets, and so on.