People often have their own patterns but they are repetitive. I like the scene in just married where they are burying his new wifes dog, and she notices his nostrils flare and therefore knows he is lying about how the dog died.
So engage them in conversation on topics you know they are prone to lie about and watch for whatever their specific pattern (or "tell" as its called in poker) is.
For example ask a guy about the size of his dick, bank account or bench press. Ask your girlfriend if the kid is yours. Then watch for their mannerisms as they lie.