One factor impacting your Google search engine keyword position is the QUALITY of links TO your website. Google places tremendous importance on the quality or "authority" of the inbound link, and most experts believe PageRank (PR) is a measure of that authority. The short version: a few links from several high PageRank pages may do more to help your keyword position than hundreds of low value (PR) links.
So how can you quickly find high authority pages with which to seek link exchanges or ad placements?
Easy ... let you competitors help you.
First, make sure you have the free Google Toolbar installed on your browser. This is very easy and quick to install, and provides you with an extremely useful tool for building your online business.
Second, visit the web site of one of your competitors. Look at the toolbar's PageRank indicator to see how the competitor's page is rated. If it is a 3 or higher, you are in luck.
Third, click the small "down arrow" nest to the PageRank indicator, and click on "Backward Links" in the drop down menu.
Voila! You will be shown a list of high authority links TO your competitor's web page. These most likely are prime candidates to visit and seek out link placements. If the links are on this listing, Google has pre-approved them from a quality point of view. Virtually all the shown links should have a decent Google PageRank.
Depending upon the competitor's page and PageRank, you may see just a few links or you may see hundreds. Some links may be from the competitor's own web site (internal cross-linking), and those can be ignored. A few links may be off-topic and should be ignored.
It is the PageRank of the page where your link appears which is critical. A linking site may have a home page PR=5, but if you link appears on a PR=1 page, your pass-thru credit is for the 1.
Ideally, you should put a priority on seeking out links on pages with a PageRank equal to or (preferably) higher than your own. However, don't automatically dismiss link requests from low PageRank pages. Today's PR=1 may be tomorrow's PR=5.
There often is at least a one-point drop in PageRank pass-thru value, and it may take a month or longer for Google to update your inbound link log.