The best way to calibrate your monitor would be to buy a hardware calibrator Spider 3,4, ColorMunki, etc).
Another alternative is to use a software (plenty online too) to calibrate to a certain extent. You can also check tftcental website and download an ICC profile that matches your exact monitor Brand and model.
I went both ways and the hardware calibrator most certainly did a better job than the other. I just spent 140.00 GBP on the Spider4Elite but you can get cheaper ones with less options.
Happy calibrating.