How do you go about designing a url rewriting 'strategy'?
I've got a clean slate as I'm helping out with an as yet un-launched site (based on url parameters) so i've no need for redirecting existing search engine results.
The first one that comes to mind is rewriting common typos. What else is there to think about?
You can rewrite complex parameter urls to simple ones to help search engines index your pages better.
Common typos can be fixed with mod_speling (assuming you're using Apache). You may also want to look into designing the web site around REST. If you design based off that concept, what you need to do in order to rewrite your URLs nicely becomes pretty obvious. You may want to Google around for introductions to the REST architecture.
The point of URL rewriting is to make more friendly human readable URLs and at the same time make the URL better from an SEO perspective.
So how will the friendly words be divided so humans and more importantly search engine spiders recognise each word? As individual folders in a URL or with hyphens to separate the words within one folder?
URLs will usually have some relation to the title of the web page. How will pages be added to your site? Is there a CMS your end users will include their own titles in? What characters will you strip from titles so they do not appear in the URL?