Hi everyone!
I am new to Japanese, so my learning methods are those that I used with my engineering stuff, which I found to work quite well. Space repetition works quite well when you need to remember stuff(There are several books on this, one was written by a guy called Tony Buzan). When you learn something separate them into different sessions. For instance, the first revision session should be done, say, 10 minutes after your first exposure to the content. The next one 1hr after that, and the next one 1 day after that. The way this method goes is towards the learner regurgitating the content: that is, you don't just look through the material in each session, you have to try to (in the case of kanjis) write it out. If you don't get it, refer back to the notes. Some will argue against the effectiveness of this method. However, there are so many methods out there that you could use.
The core factors, in my opinion, on learning anything are consistency and concentration. There's no point in doing something many times if you are not focused on the task. Conversely, there's no point in having a very intense session if you are only doing once in a while.
Hope you got something out of it
Chone