A good first aid can be found at www.dpreview.com . It's a set of greyscales, and you should ideally see the difference between all of them. Also take into account the reflection of the room and of what you wear, the light conditions,... Ideally, you should calibrate your monitor every forthnight. The main problem with flatscreens is that when you look at the monitor and make your nck a bit longer or shorter, you get completely different contrast/lightness, and there is no way to make shure that you are looking each time under the exact same angle. So there is no conctancy. Not even on the most expensive models. Their contrast ratio is also (still) lower than a good CRT's. So you won't see the same saturated blacks or whitey whites. Should you happen to own Photshop, then you have a good calibrating app.

I have tried prudent planning long enough. From now I'll be mad. (Rumi)