In would recommend two things 1) learn to negotiate
2) take an improv acting class. These classes help you learn to connect with others and read them better
Focus on your communication skills. I've worked at three start ups in the states and I can tell you that those who get promotions or more salary almost always are good communicators. Not always is it your hard skills that advance your career
When my cowokers and manager make me feel like we are in this together and treat me like a human not just someone taking in coffee and pumping out code