I've tried the flashcard method, it works great (except when you lose the card...!)
Right now I'm just trying to learn the kanji for words I use the most (I've learnt 10 by heart since starting this method 2 weeks ago) so it can work if you are willing to put in the effort
The other thing I do is read books in Japanese. This can get stressful when I know I only recognise about 2 kanji in the whole book, but then the kanji that come up often get stuck in my brain and I remember them better when I learn them!
Hope that's helpful
