Ambition is important for three key reasons: 1) It makes yourself better by pushing you outside your comfort zone, 2) It gives your life meaning by working towards goals and achievements, 3) It opens up more possibilities by pursuing ambitious plans and projects. The document discusses ambitious individuals like the founder of a training school and an online company, and someone who worked to beat Google. It provides tips for cultivating ambition such as never giving up, writing down dreams and plans, improving yourself, and believing in yourself. Ambition is defined as the desire to achieve something significant.