Well, I started out using a 'Teach Yourself Japanese' CD and book - that lasted about two weeks, then I realised I needed MORE, so I enrolled at the local technical college for night schooling in Japanese
I got my NCFE certificate, realised I needed MORE, so I enrolled for a one-year night school course in further Japanese
I got my GCSE certificate, realised I needed MORE, but found out that the college wasn't offering A-level courses in Japanese
So I advertised locally for a language swap buddy - that was pretty fun for two years, but now Mayumi has returned to Japan and I'm back doing self-study while I look for a new language swap buddy...
The important thing is to PRACTISE - if you don't use it, you lose it!