A good teacher who adapts his teaching style as per the learning style of the learner. She also has good command on what she is teaching.
Using what you are learning. Until you put your learning to practice, you do not learn. Learning by doing is the best way to learn. By doing it you make what you learned your own. For the best effect, practice should be deliberate.
Someone by your side as an additional set of eyes to give you feedback on how you are learning and how well you are practicing.
You can use this approach in almost anything in life.