why not take a photo of something and put it on your comp then adjust it till it matches what it looks like in real life. o.k so that probably isn't a good way to do it but hell, best i can come up with on the spot.
no doubt some people who work in design will point you in the right direction.
For better calibration you will need to by a colorimeter which is a hardware device used to adjust the monitor's color profile. A colorimeter will cost anywhere between $80 to $300. Generally, the more expensive, the better because of options and accuracy.