What's the most important on-page SEO element?

<h1> tag , title and Meta Description.

I have new WP sites that just have this, no content yet and with a few backlinks rank in top 10...SWEET!!!!!!!!!!

Easy. Page title. Google hasn't used meta tags for ranking in almost a decade.

Making your header clickable with an alt tag with your keywords.

followed by the h tags and meta description.

both of them are important elements for on-page SEO..

Meta and title description.

I think you need to take a look at the entire picture of what it is you are trying to do. On-Page SEO isn't just about a header tag and maybe a meta description or even meta keywords. Sure, Google hasn't used meta tags for ranking, but when you look at search results, what do you find? Just sayin'.

Anyway Maybe I can shed a little light on what I am talking about:

Search engine rankings are an important factor to consider when you have a website that needs more traffic. If your website doesn't have a good position in the rankings then no-one will find it, so you need to make sure that your website is ranked high enough to be seen (i.e. Page 1). The other important quality to getting high traffic to your site is having a nice arsenal of links. The more links that you have to your site the more traffic you will get, but also, the more links to your site the more search engines like your site. Keeping a nice supply of links pointing at your site requires similar precautions and practices as getting high search engine listings. Now, I know you are just asking about on-page, but I think it is important to see the big picture.

Although no SEO company can guarantee a high ranking for your site, here are some tips for raising your search engine ranking. Using these tips will not get you to the top unless your site is the best out there, but they will at least put you into the positioning that you truly deserve. After all, the internet is basically a free market. You will naturally flow into the place that you deserve and many search engines try to insure that you do not rise above or fall below this position. This is why they are so strict, and this is why you must keep yourself on good terms with them.

1) Content is an important factor in high search engine rankings. Make sure that you have plenty of content throughout your site with your target keywords in the articles. It's also worth doing a search for websites similar to yours and taking a look at their articles for ideas. The more content you have the better. It is generally a good idea to have (post Panda) between 700 and 1,000 words per page, but more important than a quantity of content is the quality of the content that you are providing. You cannot just put out 1,000 words of crap and expect your visitors to find it interesting and stick around for the long haul. 700-1,000 words per page really helps your site appear more to be an authority and more trusting website. At least this is what I have experienced since Feb. 2011.

2) Your website's URL can help you rank higher with the search engines if it contains your keywords. However, don't think that naming your site after your keywords will always help your rankings - you need to do more than just that. I like WordPress because you can create your URL (Article Portion) with the keyword you are targeting.

3) Search terms should be written out in text, instead of graphics. If you do use pictures (and you should), be sure to give them alt tags. The alt tags in your pictures are almost as important as text. It's also a good idea to put some of your key words in links to other pages. In the eyes of a search engine it is almost as good to have a link to a page full of the content that the visitor is looking for as it is to have the content that the visitor is looking for on your page. If a visitor is looking for something that you are linking to and he or she finds your page, they may look around your site on the way through.

4) The title of your page is very important, and making sure that you choose it wisely will make a big difference. Terms such "On-Page SEO - Are You Doing It Right?", or "On-Page SEO - Contact the Expert today!" are good to use as titles, for example - they could get you a high ranking. The title area is the most important place to include your keyword phrases, so make sure that you put the primary keyword right up front!

I use the following format for just about all my articles and pages:
-->One H1 tag
-->One H2 Tag
-->Two H3 Tags
-->An image with Alt. Text
-->Primary keyword in the beginning of the first paragraph
-->Primary keyword at the end of the last paragraph
-->Meta Keyword -- Only one keyword and it is the primary keyword the article is targeting
-->Meta Description -- Keyword minimum once and maximum twice with one LSI keyword
-->I do natural bold, underlining, and italics on primary keyword and LSI keywords only when I feel it helps the article/page and reader.

5) The navigation menu that appears on each page of your website should include your page's title. This only makes a slight difference, but we are looking for every advantage we can find!

6) Don't just use the most popular keyword phrases - the market is so competitive that you should be sure to include some niche keywords too. I concentrate on niche and micro-niche keywords. The article or page will only have about 1%-3% keyword density and it is easy to use Latent Semantic Indexing (LSI). If you are not sure what LSI is, just Google it and you will get a ton of information on it.

7) Make sure that you don't have a lot of irrelevant links on your site. The more closely related to your site your links are, the better your chances of being ranked in a higher position.

8) You need to periodically update the content of your website, even if it's only a slight change, as websites like sites that are kept updated.

9) You need to consider the fact most search engines don't like automatic submissions or multiple submissions - submit once, manually.

10) Always be on the look out for SEO news - staying up to date and using the latest techniques will help you stay one step ahead of your competition.

I hope this helps you out!

Gary

ON-SITE SEO is much, much more than titles, meta tags and HTML elements.
On-site SEO means also:

* Your site's structure like categories, tags
* How you interlink your content
* Your site's navigation

You need to see a site "as a whole" and not only look at the HTML source and check your H1 and H2 tags and descriptions This is really important to know. Alone good, meaningful categories and tags can have MASSIVE ranking power.

I would actually say that those factors like navigation, categories PLUS your content will ultimately outweigh any shortcomings you might have in META tags and HTML code.

A well designed and structured site is almost half your rankings (i am serious), but as said it goes much, much deeper than a few HTML elements within your pages/posts.

The Title Tag is the king of all on-page SEO elements. A title tag is the main text that describes an online document.

Even though RealWiz has basically said it all, I'd like to sum it up (and disagree a bit):

- Keywords in page titles - very important
- Keywords in anchor texts - very important
- Keywords in H1-H3 tags - very important
- Keywords in the beginning of your page copy - important
- Keywords in bold, italics etc. - important
- Keywords in image alt text - important

- Keywords in meta description - of very little significance
- Keywords in meta keywords - anyone still doing these??

I would say the title tags and of course your keyword density, you need your keywords in your content. Social votes like google+ and facebook likes also seem to play a bigger role these days.

Definitely the title tag.

If you have an authority site, you can easily watch a web page rank for different keywords depending on what is in the title tag alone.

Title tag...hands down.

Here are some more on page factors to consider:

- broken links and 404 errors
- HTML and/or CSS errors
- robots.txt and sitemaps problems
- duplicate titles and page content issues
- poor structure
- misused rel="canonical"

These factors are very easy to spot with WebSite Auditor Free Edition.

The <h> tags and the meta description are the most important on page SEO element. Broken links are something most web owners tend to overlook.