So I'm researching a competitors website. I run a search for their backlinks and find a few thousand.

How do I weed out the rubbish and find the authority websites that are actually contributing to the most of their page rank / authority?

I am sure that the 80/20 rule applies (I.e. 80% of the PR comes from only 20% of the links)

write each page on a seperate sheet of paper
draw a circle on the floor. size is not important!
throw all the sheets of paper into the air.
keep the ones that land in the circle.

...



...
Well it's about as accurate as any other method. Probably a **** sight more accurate than most "scientific" ones!

better still!

Ignore PR TOTALLY.
Ignore SE "value".


Link to pages your visitors might find interesting and get links that will send YOUR SITE visitors

I like to use software called SEO Elite. It will check the backlinks of a website and allows you to sort it by different factors such as PR, alexa ranking, page title, anchor text, etc.

If you are targeting a specific keyword, closely examine the links that use that specific keyword as link anchor text.

I personally wouldn't ignore PR though. It is a decent gauge of how much a link will help. I usually start by examining a competitor's high pr links, then also checking their links with the best alexa rankings.

And who is to say that your "competitors" know what they are doing?

chasing whatever your competitors do means you are always behind the game.