There is no best practice as far as coding, but I think if you google most companies, those basic pages do come up in their search results.
Your robots.txt file goes in your root directory. If you set WordPress to discourage search engines from indexing your site, it will actually create one for you.
You can learn everything you need to know about robots.txt files from http://www.robotstxt.org/
Keep in mind that search engines are under no obligation whatsoever to pay attention to your robots.txt file, although most of the big ones do.