Headings are defining the size of the the text. H1 is the biggest and H6 the smallest one. The headings are important from SEO perspective, too. Search Engines like Google give more importance for H1 text, the mort important keywords are in the title of the posts so we need to use H1 for them.( The post title size is set by default to H2 or H3.) Here is how to:


1. Find the following code in your template:
<b:if cond='data:post.title'> <h3 class='post-title entry-title'> <b:if cond='data:post.link'> <a expr:href='data:post.link'><data:post.title/></a> <b:else/> <b:if cond='data:post.url'> <a expr:href='data:post.url'><data:post.title/></a> <b:else/> <data:post.title/> </b:if> </b:if> </h3> </b:if>
(some templates have h2 , change the red numbers to 2 and search again)

2. After finding the above code change the red h2 or h3 tags to h1

3. If you think the H1 is too big add this CSS code before ]]></b:skin>
h1.post-title, .post h1 #Blog1 h1, #Blog2
h1 { font-size:1.5em; }
(this is the size what i am using , but you can change it)