According to Doi (1984), the Prophet Muhammad S.A.W used three methods of teaching;
a) verbal, which consisted the repeating important points three times and then listening to his Companions to make sure that they had heard and understood him correctly;
b) writing; by means of letters sent kings, rulers, chieftains and Muslim governors;
c) practical demonstration, such as showing the Muslims how to perform their ablutions and prayers, the pilgrimage or hajj and the fast of Ramadan.

Actually, Prophet Muhammad S.A.W method of teaching  was scientific, and his use of feedback and quality control mechanisms maintained Islam in its original form after his death and up to, and beyond, our own time. As we can see he practiced all three modes of modern teaching techniques; lectures, writing and practical.