Do H1 tags make any difference?
 

Hi,

I recently ran a test on my website to see how optimized are my pages and saw that most of them had keyword missing in H1 tag. The title contributes itself as the H1 tag, isn't it? So, how do some of the other articles rank better for some keywords even though they do not even have those keywords in their title? Do H1 tags make any difference in that case?

Yes. Not so much for you're ranking, but for your human factor. Remember you should never have more than one H1 tag per page. You can throw multiple H2's on a page for subheadings or additional content. These tags are for the most part ignored in the ranking and statical part of SEO do to their abuse and misleading use. People tend to write creative story titles that aren't necessarily related to the story.

I haven't see any diference

H1 tag can improve the ranking of the site for the keyword.

This indicates if any H1 titles are used in the web page. H1 titles are HTML labels than can help highlight important subjects and search phrases within a webpage.

H1 tag is very important, in normal it is your title