Optimize Keywords

I've always maintained that any page should target a single keyword - especially the more competitive terms. I think that many miss the point when I say a single keyword that I expect only that keyword to drive traffic. But by the nature of the web by optimizing for a single keyword, the long tail will automatically come into play at some point. source

At early stage you should target long tailed keywords or sub-prime keywords. Once your site becomes aged and receives sufficient traffic then you should target prime keywords. source

If he means both together then it will be considerable easier. If means both separately, as I took it, he's got an uphill battle. source

Yes, I researched some topic last year and when I searched on Google, I saw couple of PDF files and but they opened on PDF. So I am also looking forward to learn it and try it out. source

In my opinion it depends upon the site and what type of keywords are you using. I think an average of 9 to 13 keywords, should be good enough for a site. Moreover it is different for different search engines. source