Heading tags are important for optimal SEO. Most Blogger.com templates use html header tags sized <h2> or <h3> for the post title. In the past major search engines like Google gave precedence to tags with <h1> ahead of anything else but how important <h1> tags are today is less certain. You could tweak the heading size of your post title if you wish however take care to ensure the look of your template isn't compromised. A bigger font will result and this may mean other parts of your blog will need to be adjusted to compensate. To find out what size your blog title is look for the following lines in your template.
As can be seen this template blog title is in <h3>. To change the size of the tags just substitute the appropriate header tag where <h3> appears
<b:if cond='data:post.title'>
<h3 class='post-title entry-title'>
<b:if cond='data:post.link'>
<a expr:href='data:post.link'>&t/a>
<b:else/>
<b:if cond='data:post.url'>
<a expr:href='data:post.url'></a>
<b:else/>
<data:post.title/>
</b:if>
</b:if>
</h3>
</b:if>
As can be seen this template blog title is in <h3>. To change the size of the tags just substitute the appropriate header tag where <h3> appears
<b:if cond='data:post.title'>
<h1 class='post-title entry-title'>
<b:if cond='data:post.link'>
<a expr:href='data:post.link'>&t/a>
<b:else/>
<b:if cond='data:post.url'>
<a expr:href='data:post.url'></a>
<b:else/>
<data:post.title/>
</b:if>
</b:if>
</h1>
</b:if>
