Duccio was a typical Medieval painter – he painted during a time when it was generally believed that this world was only a preparation for the next, the achievements of individuals were not important. Duccio’ss paintings were typical of his time: static, stylised figures, no individuality, no attempt to portray scenes in a realistic setting; no signs of emotion in his pictures; people were represented hieratically -that is the most important people were painted largest, next important a bit smaller etc. No attempt to give the idea of a space in a scene: background are flat and neutral looking. In one picture, Duccio would put several scenes taking place at different times.
Giotto, an early master of Renaissance painting brought about many innovations. At the time he lived people had become to acknowledge that life in this world was important, and that people were important as individuals (Humanistic beliefs). This way of thinking is reflected for the first time in Giotto’s paintings (see his Arena Frescoes in Padua). For the first time, each scene was separate (e.g. like Raising of Lazarus; The Passion of Christ), was not put together (like Duccio) with other scenes: Giotto made his people look real (no longer, stiff carbon copies of each) – each, even angels had individual personalities. He also put his figure scenes in a naturalistic setting which might be a landscape or a home. He also tried to create space in his paintings (perspective was developed a little later by other Renaissance artists). So there is, as you see, a big difference between their paintings, and I hope what I have written has been helpful.