You need to benchmark. Get a tool like Advanced Web Ranking at http://www.advancedwebranking.com/ and try the free 30 trial. I don't actually like this software much but I am a full time SEO and this is the best there is.
After install set up your search engines, input your keywords and the software will automatically query the search engines for your keywords and get your search engine positions (it also ties in with analytics I think).
Run it weekly (or monthly) and observe the change in your search engine positions for your keywords to see if your SEO campaign is working.
Good Luck =)