SEO - on site techniques

On-site search engine optimisation techniques include:

• Content: keyword stuffing up to an optimum point, variation of keywords to cover similar and related terms - at the end of the day, 'content' is supposed to be what it's all about...
• Tags: the traditional stuff such as 'keyword' tags and 'description' and 'title' are used by some search engines, and importantly may show up in results - in SEO terms having a page which has the title tag 'homepage' or even worse 'untitled' is a major crime worthy of public flogging.
• URL's: - using keywords in a URL seems to me to be one of the easiest way to get your point across - apart from your 'index' page, other pages should be richly laden with keywords. Don't call a page 'methods.htm', instead call it 'methods_for_making_money_online.htm' or some other title that includes your target keywords and search terms.
• Pictures: may not be an obvious optimisation tool, but it doesn't do any harm to get yourself into 'google images' and the theory is that this could have an impact on standard searches (but of course no-one actually knows..). Therefore, to be on the safe side, every picture can have it's own title tag - which should have keywords where possible and also, each picture filename should reflect the content eg: the file should not be called 'IMG000345.jpg', when we could call it 'portable_music_device.jpg' or other more descriptive title.

[Note that spaces are a bit of a pain when using browsers, so I tend to use underscore instead to separate words in a phrase.]

Of these four, I tend to concentrate on content and URL's primarily, time spent on onsite optimisation is time well-spent in my estimation, off-page takes a lot of effort for few positive results..