Hi,
I followed the tutorial and I am quite happy with the result. Nevertheless, there is something that annoys me on the final result which is the smoothness of the rivets and the curved metal bar. I probably forgot something but I cannot figured out what.
Thanks
If you are using Left Click Select, (with the object that you want smooth selected) you can right-click to get to the object context menu and choose Shade Smooth.
If you are using Right Click Select, press W > Shade Smooth.
Or, go to Object > Shade Smooth.