Spotting A Liar

I've always been a very gullible person; this is in the sense that I believe daft things people will tell me, however I'm still good at knowing if someone close to me is lying about something important.

Does that make sense?

I've been going through my StumbleUpon favourites and found a site I came across a while ago about how to notice particular "Signs of Deception" in people and work out if they're lying or not.

It's only basic information, but it's very good if you can't instinctively spot a liar!