This the million dollar question and there are many ways for optimising for search. For the purpose of this presentation we'll split them up into "black hat SEO" and "white hat SEO"

Data from http://theeword.co.uk/seo-manchester/june_2013_search_engine_market_share_r...

Whilst saying that it's cheating is mostly a reductive way of classifying black hat tactics, but it's still the easiest way of framing the debate for those who are new to it.

These are just some examples of black hat tactics that have been used in the past, or are still at work today.

The theory behind keyword stuffing is that if you have a particular keyword repeated many times on a page, then Google would rank you higher for that word within search. Whilst this was true for a time, it is now easy to spot and was very bad for user experience.

Hidden content is content that is not visible to the user, but can be seen by search engines. This is similar to keyword stuffing and is designed to fool search engines into thinking the page is relevant without alienating users with poor on-page copy. Again, this can now be easily spotted and is very likely to get your site into trouble.

Spinning and scraping content are all about re-using existing content to create an impression of quality where there likely isn't any. Moreover scraped content is typically someone else's and "spinning" it is the process of modifying it so as to not be hit by duplicate content penalties.

For more information about Spun/Scraped content and keyword stuffing check out my blog on the subject:

http://www.highposition.com/blog/how-to-pick-a-fight-with-panda/

Links are still one of the most important things within SEO, they are the original quality signal that Google used when ranking a website within search.

Links pass "PageRank" (PR) and the more PR you have, the better your website will rank (in theory - although in practice its much more complex than that now). To try and maximise on PR to your site Black Hat SEO tactics include buying links which pass PR. This is very-much frowned upon by Google and, if you're spotted, can cause some major issues.

This is the most complex end of the Black Hat spectrum, but it builds upon the need for creating lots of links, but often in resorting to hacking other websites to make this happen.

Please see the following posts for more detail on how site hacks and link wheels work, and more importantly there are some tips to ensure you're not attacked.

http://www.highposition.com/blog/getting-on-top-payday-loans-hacks/

http://www.highposition.com/blog/google-loves-spam-fruit-from-outerspace/

For some idea as to the change frequency within Google here's the algorithm change history:

http://www.highposition.com/blog/google-algorithm-history/

For more information here they are: https://support.google.com/webmasters/answer/35769?hl=en

There are high profile examples of this happening, for example UK florist brand inteflora:

http://searchenginewatch.com/article/2252233/UK-Flower-Site-Banned-from-Goo...

Whilst "great content" isn't often a very useful term it can be thought of as something that attracts links and social engagement because it produces something users love. In this instance we (High Position) have the SEO bookmarklets toolkit produced by our head of SEO Tom Jepson:

http://www.highposition.com/blog/the-ultimate-list-of-seo-tool-bookmarklets...

A clear keyword focus (which isn't spammy), for this I turn back to Rand Fishkin's example which is still one of the best for those new to SEO:

http://moz.com/blog/perfecting-keyword-targeting-on-page-optimization

What is compliant changes all the time, but its essential to ensure you regularly audit your site and identify any issues which there may be within Google.

This can get pretty complicated, but Chris Ainsworth, has gone into more detail here: http://www.highposition.com/blog/the-importance-of-regular-seo-audits/

Adding value is giving something a user can take away afterwards. It doesn't have to be a literal thing like the printable CMS checklist as produced by Chris Ainsworth here - http://www.highposition.com/blog/ultimate-seo-cms-wishlist/ - but it's going over and above the expectations of a user to offer something more.

Building high quality resources like this will attract links, encourage engagement and get more visitors to interact with your brand!

Of course it's not really just Black Vs White, there's a spectrum here.

This is where we introduce the content of "grey hat" - it's somewhere in between.

*Grey

This recent quote from Matt Cutts can be found here - http://www.stonetemple.com/link-building-is-not-illegal-or-bad/.

This is a very good article on what makes good or bad link building and as it's coming from Google's head of web spam, it's worthwhile read.