Michelle Domanico, a principal in credit at investment giant KKR who previously worked at investment bank UBS, told Business Insider that it's extremely important to find a senior person in the firm who is not your boss — someone who will go to bat for you when it comes time to decide promotions and pay.

"That person can change over time, and it probably needs to change over time," Domanico said.

To get the must-read guide to the key issues at every major Wall Street bank

She said sponsor relationships develop organically, but you can still be proactive about it.

"You should notice when someone takes either an interest in you or offers to be helpful," Domanico said.

For example, you might be in a big general meeting with a senior person who says, "Let me know if anybody has questions or would like to meet about this."

That's where you can jump in.

"The difference is the young person proactively shooting that person an email and saying, 'Thanks so much for the offer. I'd love to meet one-on-one and get your perspective on these three things,' versus not acting," Domanico said.

Learning from mistakes

Domanico mentioned a few other things to keep in mind.

She said networking, both internally and externally, has been a powerful tool for her. So has maintaining her integrity. "There are lots of viral emails that go around — examples of what happens when that goes wrong," she said. "Reputations are very, very hard to fix."

She added that it's important to fail fast and learn from your mistakes.

"[How] you handle a mistake that you've made is a really defining attribute of somebody," she said. "And those are not bad things — those are opportunities for growth, and I think that failure and mistakes are actually what you learn from the most versus the successes that you experience along your career path."