Here’s how to negotiate a higher salary – or a raise. This comes from Psy Blog, a site devoted to scientific research into how the mind works.
They recommend taking the upper hand in salary negotiations. YOU should be the first one to throw out a number – not the employer.
Now, that advice goes against other articles on the subject – but here’s the research.

The first number that gets mentioned is what’s called the “anchor number.” It acts as an anchor against which other numbers are judged. If the employer throws out a number, it’ll likely be less than you want, and they’ll have grabbed control of the negotiations. That’ll put the burden on you to raise that number. And studies find that the first offer sets the tone for the whole negotiation. So throw out the first number – and make sure it’s at least 15% more than you’re willing to take. Then the employer will feel like they’ve won, when they whittle you down. But you’ll still be getting a higher salary than if they had started the negotiations.