What do you think are the most important qualities for someone to excel?

Great question, this has also been attempted earlier. Let me give you my response.
Being curious, being ready to change (often), being resilient and flexible, happy to unlearn, being collaborative, and being happy to embrace the diversity of people and ideas would definitely help you to become a winner. Telecom is a very dynamic world. Product and technologies change very fast. Organizational structures and roles change frequently too. One has to be a change leader. We also fail at times (while trying/experimenting) which is ok. Important is to be flexible and resilient, unlearn, try new things with the same determination and succeed. Building trust and being accountable are crucial. Being not too attached to our own ideas and giving equal chances to others by active listening and collaborating also helps to create more innovation and succeed more.
Hope this was useful, wishing all success.