I am a speaker of English as a foreign language. I appreciate that English is a living language and that different regions in the world use English differently. I wanted to know how I can keep up with written English, style choices, popular sayings, words often used, etc. A dictionary seems to get outdated pretty soon. I'm also not sure if there really is an authoritative source, or if the development of the language is more grassroots and less structured.
My question is: Is there some website you can recommend or some other way to keep up to date with current English?
If that is too broad, let it be limited to American English, because that seems to be what is mostly used on the Internet. Also, I'm mostly interested in creative writing.