By far, regular practice is the most important thing you can do to master a skill. This is true for learning a language, building a business, acquiring a skill, or achieving pretty much any desired goal.
To learn English, instructor Tetsuya Yasukouchi advises his students to study everyday. When asked for how long, he replies, "30 seconds." In truth, he hopes his students study for an hour or more but doesn't advise this high threshold because it leads to failure. On the other hand, even the busiest person has the chance to commit 30 seconds. If that 30 seconds ends up turning into a couple of minutes, or even a couple of hours it is even better.
Mastery of a skill seems to follows something like a logistic curve where at first progress is very slow and requires concentrated effort. At a certain point, however, improvement comes rapidly and even a small amount of effort pays dividends. Finally, that last little bit that gets one to complete mastery gets hard again, and can even take a lifetime.
For most things we find ourself at the beginning of the curve. This is why the 30 second rule makes sense, especially in this first, fragile phase of learning where effort doesn't seem to be paying off. Steady regular practice might be the trick that gets us to that second all important phase of skill acquisition.
It would be interesting to do an experiment in which you learned something two different ways. First, sit down for 50 minutes and try to learn the material. Second, spend 10 minutes a day for five days studying the material. My own experience tells me that the later would be much more effective in re something long term.