Interesting paper here by Google's founders while they were at Stanford. Gives some insight into what google is looking for.
http://www7.scu.edu.au/programme/fullpapers/1921/com1921.htm
Basically google is designed, maintained and updated so it can not be fooled and it provides the best search engine in the world. It is looking for the best page on what you are searching for.
So the question should be what are the search words your future webpage readers are using. These are your keywords. Your webpages should be based on these words.
At the end of the day content is king. If you have no content, trying to trick google will not work. You need the content first, then SEO the site. That's when you can use a professional.
Google looks at heaps of things...meta tags are not really one of them. Other search engines do though so it is not totally wasted. Google likes, descriptions, all the headings, fonts, text, density of keywords in text, alt tags on graphics and pictures. The first 100-200 words of text seem to be important. Do not use hidden text that is the equivilent to spaming to google. Try to spread your keywords around the site not all on one page. Maybe 3 to 6 per page.
Pagerank - is a ranking system for webpages. Think of it as webpages all voting for each other to see who is the best 10/10. It does not penaltise you for your incoming links but it can for your outgoing links (doesn't like link banks). What most people miss is that half of your pagerank comes from your internal pages - see content is king. If you have more links going out to a page than coming back then you are giving PR away. All your pages should link back to your home page or your most important page. So the architecture of the site is important. Think it of funnelling PR around your site.
It not hard to customise your site yourself. There is lots of help on the internet. i can post some more links if you want in a couple of days. (there at my office not on the mobile)
For PR/google domain name relevance. Google has always crawlled with DNS info in hand. So it knows if all your domains are on one server and linking to each other. There are rumours google has been recently optimised to look for domains catching traffic. Maybe a recent change in ownership will trigger a no vote and hurt PR and search results.
All cat and mouse stuff.
There's a good site - I think it is googleguy.com - he seems to have a lot of experience and tips and hints.