Optimize your website with high traffic keywords and get high ranking on Google search. Use keywords in meta tags and title tag and also include keywords in URL. Make your web content search engine friendly and also make it suitable for human visitors.
It's the keywords that would take your website close to your targeted audiences. It's the keywords that would bridge the gap between your website and your customers. It's the keywords that would highlight your website for your clients. SEO is the game of using keywords.
Google has a set process for indexing and ranking websites. It ranks every website on certain factors like site navigation, content and back links. Also it considers downloading speed and internal linking of the sites. Slow downloading speed and broken internal links make a website unreliable.
How to optimize a website?
The only answer to your questions "referencer gratuitement mon site sur google" is to take help of a senior SEO consultant. The consultant would see design your website and also analyze its content and internal linking. The SEO would suggest some changes in the design and also suggest changing the web content.
The SEO would find keywords for your website and suggest incorporating the keywords in the meta tags and title tags and in URL of the site. The process of changing content might take some time but it would give excellent results. Find an experienced SEO consultant as it is only a senior SEO guy that can be answer to your question "referencer gratuitement mon site sur google". The SEO would drag your website from bottom to top of the search engine page.