Google and other major search engines gives importance to the header tags in the following order.

h1 tag
h2 tag
h3 tag
h4 tag
h5 tag
h6 tag

First prioriy is given to the h1 tag because the h1 tag shows the theme of the topic discussed in the page. As a wel orgganized web page is oriented on the single topic usage of h1 tag on a page is limited to 1. If we use more than one h1 tag on the same page it may lead to google penalty.

H2 tag is used for placing the sub titles on a page. As the number of subtitles on a page increases the usage of multiple h2 tag is not treated as spamming on the page.

The page headings structure I prefer is demonstrated below.

h1 tag [Post title]
1. h2 tag [sub title]
1.1 h3 tag [important point]
2. h2 tag [next sub title]
2.1 h3 tag
2.2 h3 tag

To know about the title tag and its placement on a synamic site click on the link below.