I understand key words. I think mine are probably as good as I can get with the knowledge I have, and over time I can update. However there is something that I wonder. Someone talked to me about how for £500 they can optimise the site for me and use keywords. They talked about a folder on the homepage.
I would have thought from the little I know, that key words were only a part of SEO. linking and the search engine submission spring to mind, as does advertising.
What if I did want it should I expect from web site optimisation that I can't in the end, do for myself with a little time and learning? Seems a dangereous area if you are not too knowledgeable and easy to get very ripped off - seeing I have seen the same service for £200.....
Find out how much time and learning you would have to put in to accomlish the same as the SEO. If it is more and you are not wiling to wait then you better sign up. If it is not that much time, then see if you can do as much as you can yourself.
Find out whether the SEO will be saving you time and effort in the end. There are several reputable SEO's out there who would provide the service to you for a fair price. I do not recommend you hire the cheapest or most expensive, find someone in between. Keep in mind you pay for what you get out there.
You may want to handle all the basic stuff yourself and then outsource the stuff you do not have time to learn or do not want to learn. Thats what I do!
If you need more information PM me and I can give you some pointers on keywords and where to start other than keywords.