How can i shine at work?

I am the youngest and only junior at an architectural firm, therefore I always feel like I am making mistakes or not knowledgeable about anything. Because of this I always feel like the odd one out, and I feel like my boss is frustrated with me. Not only this, but everyone is always working. When I come they are working, when I leave they are still there. I am contracted to work 8 – 5 and I do what I am supposed to. But how can I shine, although my skills need sharpening? How can I impress the boss even though I am on the lowest rung of the ladder in every way!??