I just came here, but the best tip I can offer is to set up a goal that requires you learn Japanese to get that goal. For me I want to learn Japanese so can become fluent, so I have another lens to view the world through, and pick up chicks.(just kidding) Maybe you want to setup up business in Japan and being bilingual will help that business. Anything just find a way to link it to a goal, then break that goal into smaller chunks.