If a page on your website is penalised, it will not perform as well as it might in search results. Here are some tips to help avoid penalties. In the case of a new website, it may never get to perform well in the first place.
Remember that outside Google, no-one really knows what counts as good or bad in terms of SEO. There is some general advice from Google about having good, unique content and quality backlinks. Other than that, people are justing using their experience and guesswork to find out what works and doesn't. A lot of SEO information online is copied and spread as online myths.
With this proviso in mind, here's a fairly non-controversial list of things to avoid.
- Avoid Exchanging Links
Excessive link exchanging should be avoided as Google may see this as an attempt to artifically improve rank. A few link exchanges will be OK but avoid large numbers. Link farms - where a large group of sites hyperlink to all other sites in the group should always be avoided.
- Do not Sell links
Selling links is a no-no - unless the hrefs use the nofollow attribute. If your site sells dofollow links and Google becomes aware it may well be penalised. Google's WebMasters site allows people to report paid links. Rumour has it that Google may use this information to adjust its algorithms to improve detection of paid links.
- Do not buy links
Recently, Google has threatened to penalise sites they discover have purchases dofollow links from another site. Logically thinking though, this does not seem possible - or at least it would be extremely unfair! If this were to be the case it would be easy to penalise a competitor by purchasing links to their site and then reporting them to Google.
- Avoid duplicate content
If possible, avoid duplicate content. For example, don't make the same post to two different blogs. Google will ignore copies of content. A few copies will make it into Google's index but lots of copies will be ignored. Even on different pages within a website, try to keep the textual content unique and avoid repeating whole paragraphs of text.
- Don't stuff keywords
If you want to perform well for a certain keyword, stuffing your webpages full of the keyword will not help. Write you copy in a natural way so that it reads well. If you are writing a web page about Google penalties (for example), the keyword "Google Penalty" will naturally appear a number of times - you don't need to repeat the phrase scores or hundred of times.
- Don't include hidden text
Make the contents of the webpage visible to the user. For example, don't include extra content such as white text on a white background that the user cannot see.