As a foreigner who experienced the process of learning another language both in schools and in the learning-by-doing method, I can state that both of them are extremely important in the process of achieving proficiency in a language. My method relies in teaching strong grammar rules and apply them in a conversation with a native speaker. Mistakes, in my view, are part of the process, it is only through mistakes that people learn a language. From me you can expect, depending on individuals' needs and goals, a mixture of theoretical background and its application in a conversation. Depending on each other level at the time of starting and everyone's goals, these will be adjusted accordingly! Moreover, I consider essential learning the culture that stands behind a language to achieve proficiency. Thus, learners should expect going deep in the Italian culture and understand why we speak in a certain way. This will not only benefit command of Italian, but it will make learners more open minded and curios about spending some time in Italy, to apply what they learned from me with people that may have a completely different accent compared to mine.
Let's not play it cool, Italian is a difficult language and like every difficult language, the best way to learn it is by practising and speaking it with natives, to achieve proficiency faster and better.