What is the best way to learn English grammar?

Here's a question that I answered on the Q&A site Quora about learning grammar. It's a topic that I've written about before, but that was a long time ago. I think it's a point that should be repeated.:

Question: What is the best fun way to learn English grammar?

I think my grammar is reasonable. However I can never remember the difference between a noun and verb. I'd like to properly understand (most of) the rules of English grammar but i have a busy life so it would great if it was actually fun and can be learned/learnt (that's one of my weak spots!) as a relaxation.

Aaron Knight, PhraseMix.com author:

PhraseMix.com author and expert on the English language.

There are two separate ways that you can "learn" English grammar. One is to learn it as a subject. This means learning the names of parts of speech, from "noun" and "verb" to "2nd conditionals" and "dependent clauses". I recommend learning grammar in this way only if you're going to be a language teacher or if you have a strong academic interest in this topic,

The second meaning of "learning" English grammar is learning to use it in speech and writing. To do this, it's important to remember the following points:

• There are really at least 2 versions of English grammar: one for spoken English and one for formal written English. Almost all of the "rules" that you read about in books and websites are for written English. These rules may not apply to spoken English.
• You need to learn a little bit at a time. If you try to read a big book of rules and remember all of them, you're going to forget most of it. And even if you do remember, you probably won't be able to apply the rules to your own language.
• There are a lot of topics that can't be learned with a simple rule; they require memorization. For example, you have to remember that "the" always goes with "The Unites States", "the sun", "the Beatles", etc. There's no simple rule that can help you figure that out.

The course I recommend is:

1. Get a reference book and read it for 5-10 minutes at a time when you have a question about something.
2. Find example sentences that illustrate a grammar point you want to remember. Memorize them using flashcards and by repeating them over and over.
3. Spend the rest of your time reading, writing, speaking, and listening to natural English.

Do you have any methods of learning grammar that have worked for you? Is there a book or website that you've found helpful? Let us know about it in the comments!