SEO EXPERTS: BEst way to rank a NEW landing page?

Hi Guys I have been lurking round in the Warriors for Hire section and I have seen dozens of offers from highly talented Warriors when it comes to provind SEO services. I have a question though which I want to put out there to get feedback on so I know which way is the best way to move forwards.

I have a landing page - a one page sales page - that I want to rank on the engines in my local area for a specific keyword.

What would be the best strategy to employ in your opinon?

I have heard lots of ways to get rankings, but this particular scenario seems to be the hardest, so my questions revolve around the following sticking points?

Should I buy a new keyword-matching domain?
Does it matter that it will only be one page of content? Will that affect the ability to rank?
Would it be best to just make the landing page a page on another domain and use the keyword to make the name of the page:

www.keyworddomain.com vs www.something.com/matching_keyword.html

If I use a video for the landing page sales letter instead of long copy will this hurt the chances for ranking?

I know there may be some conflicting ideas, but Im looking for an overall best approach... and hopefully some lively debate

Dave