When trying to make yourself back in shape, you need to understand what is important regarding diet and exercise and then implement your plan (the method). Further, you must keep doing it for months, if not years (persistence) and it would be ideal if you know why you want to lose weight (motivation).
In the context of language studies, the method includes your learning and practicing materials and the way you use them. Besides choosing the right materials for your level and learning style, studying or using them effectively is at least as important. In addition, you can't learn to speak a foreign language without persistence, which means studying/practicing almost everyday and continuing this habit for years to come. For many people, being aware of the tangible benefits of speaking the language fluently provides much motivation, which helps maintain their persistence and benefits them immensely in their studies in general.
If you integrate the above elements in your studies, your success will be just around the corner.