The only reliable way is to get a calibrator, of which there are several on the market, from x-rite (i1 Display, ColorMunki) or Datacolor (Spyder). Prices from a little over $100 for the entry level editions, and upwards.
The best value for money is probably the i1 Display Pro, at $250. That's about what you pay for a 500GB SSD these days.
High-end displays from NEC and Eizo have their own, integrated solutions.
The calibrator corrects the display on two levels. First it calibrates to a white point and a black point, in the process neutralizing R = G = B relative to that white point. This is a global adjustment that affects everything.
Then it writes an icc profile that describes the unit's response in that calibrated state, and in great detail. This profile is used by color managed applications only, to correct the data that get sent to the display. This correction uses all available parameters, including the position of the primaries in three-dimensional color space. The profile doesn't correct anything in itself, it's just a description, but it tells the application's color management module how to correct the data for display. This way the file is reproduced accurately on screen.
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D Fosse is correct: only by investing in a hardware calibrator will you be able to properly colour manage your display(s).
The "professional" multi-screen calibrators are more expensive, though, with the cheap editions often missing the ability to colour correct more than one screen (and lacking other useful options).
Solution: get DisplayCAL (open source and free, with multi-screen support), and purchase a base model calibrator. Saves money, and you will have options that are ordinarily only available to users with higher-end calibration devices.