Google has always given high importance to the quality and relevancy score in its search algorithms. In line with this principle, doing the wrong things on your website can make Google give you a low quality score and push your site to back of search results. Although many experts use the term Google Sandbox, I prefer to use Quality Score as a term since the existence of Google Sandbox is itself debatable.
Most of the below techniques apply to most search engines, not entirely for Google only. Always remember the most important rule – make the website for human users and not for bots, with this ground rule in mind, you will begin things right.
Never use Hidden texts– Filling your page with texts too small to read, or same color as the background and or using css for the sole purpose of loading them with rich keywords content will earn you a penalty. SEO Experts will always advice against this.
Never do Page cloaking — This is a trick to make visitors click on something that you want but the visitor originally may not want to go to there. There is a common practice of using browser or bot sniffers to serve the bots of a different page other than the page your visitors will see. Loading a page with a bot that a human user will never see is a definite no-no.
Link farms– Be wary of who and what are you linking your website to. The search engines know that you cannot control your links in. But you can certainly control what you link to. Link farming has always been a rotten apple in the eyes of search engines, especially Google. That is reason enough to try and avoid them.
Multiple domains having the same content — Search engines look at domains IP’s, registry dates and many others important net metrics. Putting multiple domains with the same exact content will not go un-detected and will result in low rankings.