Use of meta tags in the process of search engine optimization

[Bizviz Advertising]

what r the rules and process to create good meta tags to optimize a website effectively. More specifically, if any one use a word twice or more in the key word meta tag or title meta tag will it be a negative according to google? Google didn't say clearly about this matter. Plz help.Thanks in advance.Check my website and suggest me.website is : http://bizvizadvertising.com