A friend of mine is a Web Developer, google site mapping is a must, do not over use key words (Google hates key word stuffing when crawling your web pages), think about any links you have on your site, are they relative to the key content of the services you are promoting - you are far better to have four relevant links to your site than 15 non relevant links.
Another way to stay ahead on Google rankings is to update your home page regularly again, when Google crawls your site, it will see that it is an active site. I also think that to have a site Mcaffe Site tested is a plus, it certainly does no harm. Finally, really get to know Google Webmaster Tools, Twitter and Face Book are great, so long as you keep everything content relevant.
Just a few pointers proven to work, and it is more than possible to get good rankings without all of the expense of SEO.
Hope this helps.