That's right . . . learn.
Like I used to tell all of my young Sailor's who would get discouraged with setbacks and lacked ambition - success is like a video game. You have to know which buttons to push and when. If you get knocked down you have to figure out which way is the better way to get ahead. In other words, keep learning as you're progressing.
This learning doesn't stop when you become a supervisor, director, or even a CEO. Part of good leadership includes continued learning. No one can ever get to ANY level and say, "I now know it all". But how many leaders have you ever had that had just that mentality. I've had "a few".
Jim Rohn once said, "The book you don't read won't help." Makes sense, doesn't it?
Make a habit of reading books - any subject you're interested in is out there and just waiting for you. Read trade magazines or blogs. Go to local seminars or complete online courses (there are a lot of free ones out there). There are so many resources out there for you to learn from. There's no reason why you shouldn't be taking advantage of them.
"No time", you say? Wrong answer. Make time. A blog only takes a couple of minutes to read. Start by finding a couple that are published by notable "experts" and go from there.
You're never going to know it all - realize it and believe it. You need to keep learning. Google "leadership blogs" and/or "leadership books" and get started now.
