Thanks for clear my confusion and solved my problems now today i changed it meta tags and meta description and search right keywords for my blog.
Of course they a used. The text size weighs out more to google than your normal text. Bolding is also a must as well within your articles for keyword phrases.
Oh yes!! They are pretty useful.. Not only in Google, but other search engines also give them importance.
I think they most definitely are, <h1> more than the rest, <h1> for your primary keywords, and the rest for your secondary keywords
google crawlers will think H1, H2 tags inside these keywords is important,So select the bold keywords
H1 and H2 have proved very useful for my sites. What I also find a great help is placing H5 (though small) listed right at the topmost of my pages listing important keywords too.
It doesn't really matter. Your content, and its quality, is what helps for better ranking. You can optimize with header tags all you want, but when your content is great, why do you need them? You don't, focus on getting links, and having quality content.
Despite all the hype that it makes no difference, I think it still holds some value. I think this was confirmed before but the key thing is not over doing it.
Yes they add more weight to your keywords in search engines. Anything lower then h3(h4,h5..etc) is useless as there in no additional weight added in.