Be more loyal to your company than the company is to you. I've managed too many teams that have entry level employees and I see this too often. You like your first company, they gave you your first real shot! You should be loyal, right?

Wrong. People stay in an entry level position for too long believing their employer will "take care of them" if they just work hard enough, stick around long enough....

Over time, this grinds a person down. I love that people believe that if you just work hard and do well your talents will be recognized and you'll be promoted, but the truth is this isn't always the way things work. Companies both large and small have to have a position to promote you to, a budget to pay you more, etc etc....

Once you've been at your first job for a bit, begin engaging your manager about what your options are for developing your career. If you start to get the sense that no one ever gets promoted, or that options for advancement are limited, then change gears: Learn what you can where you are and take that experience somewhere else.