What I am going to put forth here is mostly per page
, not per site
. Each page is an individual to search engines and people searching.
With search engines, it seems that if everything on two pages are equal except one, the one that is different will win the higher spot. As example, if your page and my page are equal in all except age, the one that is older will be above the other.
Following that thought, you do not always have to be the first listing on the search results. Being on the first page can be just as good. In some cases you may still do well on the second page or so on.
Here are some of my thoughts on how to SEO.
The Title of the page
The "Title" of you page is important. The title tag in the HTML of your page, limited by length restrictions, is the link to your page that shows on the search results. As example, if you titled your page -The Weather of the World-, Search engines would index it as such and people looking for that sort of information would be apt to visit that link.
Keep the title short and to the point of what the page is about. Remember that there is a length restriction on the search results. Somewhere between 10-70 character, counting spaces, seems to be the general consensus. As example: "This is a wonderful place on the internet to find information on and about ClixSense" might be cut off at the "a" on about, depending on the search engine.
Make the title meaningful and be sure it matches the subject matter of you page. If your page is about the history of weather, make the title match that. A title of "The Weather of the World" might seem ok, but a person looking for weather history might skip that listing even if it is the first on the results page.
"Content is King!" You might have read that. It is true, but there is more to it than that. Search engines seem to have to places they use to get the snippet of the page content that shows in the search results.
One place is the meta tag named "description" <meta name="description" content="put your description here.">
. Again, there is a length limit. Somewhere between 70-160 character, including spaces, seems to be the consensus.
The other place that search engines might get a description to display in the results in from the content of the page. There is a lot of opinions on this bit. Some think that the first 70-160 characters of the first paragraph are used and other think that the description is chosen from different places in the content of the page. I agree with the latter when applied to Google.
In either case, you want the content to be informative and match what the page is about
These seem to be almost archaic, but it doesn't hurt to have them. Again, the rule is to match what the page is about. About 10 keywords or keyword phrases are enough. What! Keyword phrases?!?
Um. oh, yeah. Um, you can use short phrases as keywords. Ten three word phrases seems to be the general consensus as a limit. Each phrase or keyword separated by a comma. Example - <meta name="keywords" content="this phrase, phrase, a good phrase, some other phrase">
Important also is the domain name, as Valerie mentioned. "monsters.com" would not be a good domain match for a site about weather.
A Google result
Let's look at a search result for the term the weather of the world
Weather around the World
<- This is the title of the page. Only about 24 character, including spaces.
www.timeanddate.com › Time Zones › World Clock
<- This is the domain without the http:// prefix.
across the world
. ... Local time and weather
around the world
. °F; °C · Abu Dhabi, Sun 2:02 PM, Passing clouds. Mild. 70 °F, Damascus, Sun 12:02 PM ... <- This is the description from where ever it was taken. Note the bold and the "..." that indicates the key search terms matched and concept that these words were taken from several places in the content.
Please forgive the length of this reply and any grammar and spelling mistakes.
The html I used as examples would probably not be needed when using the methods in Valeries walk throughs. Just typing in the keywords and the other information as instructed would be all that is needed. I used the html for those that might be trying to code there own html.
All of the above is just my thoughts and experience. As noted by Valerie, search engines are in a constant state of change. What works today might not work tomorrow. I do, however, think that the title will continue to be important for both the search engine indexing and getting people to visit your page.
If I were to put importance to each, I would go this way:
1. Age of site. How long it has been online.
2. Title of page.
3. Content of page.
4. Domain name.
Good luck to you all.