First, you must know C++. Know how to properly debug your code. Be able to architect game systems intelligently, i.e., look at how other similar systems have been implemented and work that design into your game. Stay transparent in how you code. Make sure your lead knows how you are solving the current problem. Keep focus on your work. Don't get randomized - stay on target. Finish games.
This summer I helped change the world. Well, not really, but I took part in a movement that is. I was in a summer program called Girls Who Code, which gives high school girls a crash course in how to program in order to close the gender gap in the tech world. It was a ton of fun, and I found out how important it is that girls code.