Salary secrets and myths

NEW YORK (CNNMoney.com) -- When it comes to negotiating money, it's hard not to feel like you're at a complete disadvantage relative to your employer.

For starters, you don't really know how much the company can pay you. Not really. Often, you only know what your manager (or the hiring manager) tells you.

You also usually don't know what your colleagues make -- and, let's face it, "colleague" is a generous description for that guy down the hall whose biggest accomplishment seems to be showing up.

And often you don't have any idea how the company arrives at its pay decisions. It certainly feels like some of those decisions are influenced by how much the boss likes you or a co-worker.

To shed some light on the more dimly lit corners of compensation, following are six secrets and myths of pay.