Crivens it was before the Internet and I had a broken heart and nothing to do. Basically, in NYC, it was easy to wind up spending weekends speaking no English, save, ironically at a karate doujou.
Also ironically perhaps, in the end, I married a Japanese woman whose English was (and is) better than my Japanese and my Japanese has gone way downhill. But the short answer is, I wound up, after the broken heart, making a lot of Japanese friends who wanted to learn English and also, having the time to sit there at night going through the boring repetitive exercise like is this a book. Yes it's a book. Is this a book. No it's a house you moron, can't you tell the difference between a house and a book? (I may be remembering the sentences incorrectly).
A great deal of it was being able to make a lot of Japanese friends at the time. I would take classes as well, but most of my classmates were just learning it for business, whereas being able to sort of use it in everyday situations and of course, the incentive of trying to fix the broken heart by finding another girlfriend helped too. I was never great at writing--at best, I may have known 500 characters, but did know all the phonetics.
Doing karate at the time, and trying to impress the Japanese instructors also gave me incentive. For writing, I started with the phonetics and was also taking classes at the Japan Society and they were pretty good about integrating the reading and writing with the speaking. Don't want to take this too far off topic, but if you have other questions, feel free to PM me.