The Renaissance was an incredibly important turning point in Western Intellectual and Cultural Tradition. All of these changes centered around the idea of Humanism -- in which, people became less "God Centered" and more "Human-centered". I have narrowed down these changes, and will discuss in detail, these changes in three major categories: Political, Education, and the Humanism of Arts.
The major political changes of the Renaissance were from the old Feudal System of the Middle Ages into a more flexible and liberal class system. This was most noticeable in Italy (particularly in Florence), where the divisions consisted of the old rich, the new rich nobles, the middle class, and the lower middle class (the poor didn't count). This created great conflict between these social divisions. The new rich consisted of successful merchants, capitalists, and bankers, innovators of new systems of making money. The Humanism philosophy was also a very popular with the people and many political leaders rose to high positions with support of these ideals. Three humanists even became chancellors of Florence -- they used their rhetorical skills to strongly rally the people of Florence against their enemies.
The great changes in Education of the Renaissance were inspired at first, by the desire of Humanists to be wise and to speak eloquently. The idea of useful education for the people, and very "well rounded" schooling in many different fields of learning were the new defined goals of Renaissance education. People all over (Especially in Florence) revived the Ancient Greek studies of Plato, Aristotle, and many others. People began seriously questioning what these people said and re-developed the "Scientific Theory" in which you didn't just accept whatever was said to you, but you tested the truth of it.
In the area of Humanism and the Arts, Renaissance Artists no longer were subordinate to the interests and the values of the Clergy, and were able to create anything of their "artistic will". Both men and women were now able to appreciated arts beyond just religious themes. Artists could also now take advantage of new techniques, such as oil painting and linear perspective to enhance the quality of their works. All of the great artists of the time used became who they were solely because of this new artistic freedom that the Renaissance brought them. These artists also created works that were more complex than before. Taking advantage of this, artists such as Leonardo da Vinci -- the ultimate example of the Renaissance man working in all types of educational fields, and Michelangelo who was possibly the most famous artist and sculptor in history.
As you can see, the Renaissance was to great extent and a major turning point in history from the Middle Ages in just about every element of the Society. The Renaissance has truly become the original roots of our culture from the West. This was the time when people questioned the past, and decided to go back to the schools of learning taking the past of the Greeks into their present to make a better future.