I had the same problem and wasn't able to determine my skin tone for ages... I know now that I am definitely cool-toned, that is have skin with pinkish undertone (NW in MAC). But I think this is sometimes very difficult to see (even on your own skin) - I would never say my skin looks pink at all. I did a lot of research online before I found out...
One way to tell is whether you sometimes have redness on your skin? This is how you can tell the pink, cool undertone.
If your veins are both blue and green, you might be neutral though. Its easier to see this as well when you skin is not tanned (i.e. in winter). Do you have any friends with a warm undertone that you could compare to? Many Asians types have a warm, olive undertone, where you can clearly see the yellow undertone, which makes the veins looks more green. Its easier to see that way whether your veins are more blue-ish in comparison.
You could also try out holding some clothes underneath your face. Cool toned skin will look better in navy,blue-toned purples, bluish greens. Warm toned skin will look better in more orangy colours, like warm browns, yellow-based reds, yellowish greens. If you say orange eyeshadow doesn't suit you, then you might be cool-toned indeed. Don't be too strict with what clothing colour suits you though, because there are also differences in light versus dark and also hair colour plays a role. This is just to get a feeling for cool versus warm.
The tricky bit is that the colours that make our eyes pop are not always the colours that suits us well (orange helps blue eyes pop, but might not be the best colour for cool toned skin), so its about trying out different shades of that colour (for example an orange brown, which is not too warm) to find the perfect match.
Hopefully this helps a little bit!
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Have a look at the following video, it summarizes everything and it also explains that different cosmetic brands means different things when they say "warm" and "cool"
http://www.youtube.com/watch?feature=fvwrel&v=wbjplEiSncY&NR=1
And this video is about colour theory, so which colours complement each other or balance each other out:
http://www.youtube.com/watch?v=XBb3mtQKhgM