I have a foolproof technique that everyone is welcome to use: I don't apply for positions that I know will pay less than what I think I'm worth. Otherwise, if the interviews go well and I'm happy with them and they're happy with me and they want to move forward and make me offer, and the offer seems to low, I ask them to increases it. If they don't, I don't take the position. If they do: voila, mission accomplished! Crazy, I know, but this one crazy trick really seems to do it.