I know it's a lot of work, but the best strategy is to interview for jobs consistently and regularly, regardless of whether you are happy with your current job. Shop around your offers, get companies to fight over you. Use all the leverage you have. You don't get more money without demanding it.
Power and money are never given, they are only taken.
Paradoxically, the BEST time to job hunt and negotiate is when you're in a job you really like.
This sucks, of course, for all sorts of reasons, but it's amazing how much "Actually I really like my current job, so you'd need to pay (some big number) to get me to move" will sway people more than "well I think market rate is about X"