I'm trying to optimize my [website](https://www.google.com/webmasters/tools/home?hl=en) for better search results, I currently have a meta tag created for keywords like so:

    <meta name="keywords" content="key1, key2, key3" />

I have waited 30 days and still when I search my keywords, my site does not come up. How should I be writing my keywords for better results? 

My website is based on WordPress.