I lived in Tokyo for 2 years, studying Japanese full-time, and completed several courses in Finland before that. Speaking came pretty easy and I am quite fluent in normal conversation, but learning kanji has proven to be a real time-sink and a source of frustration, although at the same time I love them for their beauty. Also reading Japanese feels different than reading languages in the Latin alphabet, as the characters have an extra layer of meaning (not a huge difference, but helps to distinguish homonyms + create new kinds of puns / emphasis).
There are roughly 2000 kanji that you should know to be a high-school level reader. The latest test I took (http://www.speedanki.com) shows I know about 800. Reading a newspaper is not possible currently, as I would have to constantly look up kanji, and often the important words are the rarer ones.
But I will learn them. At this point it's an obsession, I'm not even sure why I need to know them, except to prove to myself that I can.
But what I really meant were dead-tree books and newspapers that I could read while not at the computer.
It may be painful, but it should be possible; yes, you'll have to look up the kanji, over and over -- writing them down as you look them up -- and it'll take you half an hour to read half of one article. But if you keep at it, and keep looking them up, every day, you will improve -- you will learn them! You just have to tolerate a lot of tedium on your way.
Yes, I have seriously tried it. Maybe it works for some people. It's of course quite hard to recall why you really remember something, but in the 800 kanji I know according to the test, the vast majority I seemed to remember from seeing/using them in context while reading/writing Japanese. Mnemonics are an attractive thought, and I hope they do really work for some people. Personally I am a bit skeptical. My feeling now is that learning doesn't have to be brought up to conscious thought, but is something that happens naturally as you re-encounter things. http://en.wikipedia.org/wiki/Spaced_repetition
If you'd like, you can combine these two things too. http://kanji.koohii.com/learnmore.php
However, in order to become fluent in a language, you need to think in that language, which means you need to build up concept associations in that language. By teaching yourself e.g. English mnemonics when learning Japanese, you are irreversibly tying your Japanese knowledge to your English, and giving yourself a handicap in acquiring fluency.
If you instead remember a word by memorizing a specific use / context of that word in the target language (and add some visual imagery to that for good measure), then this gives you memory associations that will actually remain useful as you become a better speaker. This is why immersion works so well: your entire learning is grounded in the necessity of speaking with and understanding the culture you are living in. If you need to eat, you will develop a food vocabulary very rapidly.
Mind you, I speak about four languages, am fluent in three and grew up naturally speaking two, so maybe my brain is also wired differently than most.
The problem is that Japanese has the most complicated written language in the world. It has two alphabets and a set of many thousands of symbols (kanji) borrowed from Chinese. Learning spoken Japanese is an entirely different undertaking than learning written Japanese.
You can be completely fluent in Japanese and still not be able to read a newspaper (this may actually be more common than not).
Rhythm is an important mnemonic aid. The Homeric epics are poems because poetry has meter and rhyme, and people needed that to remember the whole thing. Same thing with Kanji.
"In June 2004, at the ripe old age of 21, all post-pubescent and supposedly past my mental/linguistic prime, I started learning Japanese. By September 2005, I had learned enough to read technical material, conduct business correspondence and job interviews in Japanese. By the next month, I landed a job as a software engineer at a large Japanese company in Tokyo"
Basically, his method involved constantly immersing himself in Japanese media.