Use h1 only once.

abuse h2/h3 as much as you like to make your site look pretty.

No it won't rank your site.

H1 should be reserved for your post title which is automatically placed within H1 tags. Use H2 and H3 within your post anytime you want to use a heading. I use only H3 within my posts as H2 tags appear too big to my eye.

H1 is your main heading

H2 is your secondary heading 1
H3 is the sub-section of the secondary heading 1

H2 is your secondary heading 2
H3 is the sub-section of the secondary heading 2

...and so on and so forth.

Remember that search engines check the keyword consistency between the header tags and other parts of the page.

Also, you should not use more than one H1 tag on a page unless necessary.