I’m trying to rank for a particular keyword in the serps & I’m
going to use document sharing Sites like docstoc.
When I create a pdf document whats the best keyword density
and do I need to make the keyword phrase hyperlinks, put quotes
around it or just leave it like a regular phrase in the pdf.
I’d agree with what’s been said, just concern yourself with the quality and people will view it. In this case, having a well designed and illustrated pdf might make it pop more on public sharing sites such as these.
Also, if you have a website, you should always start there. I’m a fan of having an HTML page for all PDFs I plan on showing - some people like the page, some like the PDF, it’s good user experience.