Here are tools and tips to keep your search engine ranking by checking on what your competitors are doing.
Spyfu is a great tool to quickly see what keywords your competitors rank for in the natural and paid search results. Find out what ad copy they use, their daily ppc spend, and track changes they make. This is a great place to start for competitive data mining.
The keywords your competitors use may converting better than your keywords. You can use adsense to test what sites will be triggered for what keywords.
Check who links to them using tools such as opensiteexplorer.org, yahoo site explorer and majesticseo.com this can give a good indication of professional partners and associations you may wish to join.
Check online information hubs including PRWeb search, Digg.com, and article aggregators such asDetails