The smartest people who succeed in their careers for the long-term never stop working hard, never stop building relationships, and never lose touch with their own strengths and weaknesses. The day you start mailing it in is the day you can start packing up your things.
Being smart isn't enough. Being aggressive isn't enough. Being confident isn't enough.
The only way to succeed in the long term is to put what you do first. The only way to do that is to know why you're doing it and believe that your mission is so important that you owe it to yourself and others to work at it relentlessly, no matter how long it takes, no matter what new skills or partnerships you need to be there.
When failure is not an option, you have no choice but to persevere.