Single Ladies, share your tips on how do you deal with longing for a partner

I know, I know, this topic keeps coming up every now and then. But I'm feeling particularly blue right now and could use some uplifting thoughts, specially from women in their late 20s or 30s.

How do you deal with this when most people around you are coupled up? How do you deal with the jealousy that flares up every now and then (this may not be the case for everyone) when you see your friends in happy, loving relationships?