How to decide meta keyword for Google Search Engine

I've to decide the meta keywords for my website. I want to decide them carefully for google search.

开发者_如何学编程I have 2 questions about it:

• how many keywords should I use ?
• my website is in italian, should I use both english and italian keywords ?

thanks

note that google ignores the keywords tag

Don't go too crazy. Meta Keyword isn't something that Google rates very high (if at all) on its list of things that move you up in the rankings. It's due to the fact that not too long ago, people would load the meta tags with "hot" terms so they would get all sorts of traffic. The search engines got smart.