Almost nobody is good at them। They are hard to write. It's difficult to know what to say. They are hard to read. You know that no matter how well you do it, it's going to be painful to read, because that's just the way it is.
Those left behind feel pain whether you write or not. Open yourself to those in grief and don't be afraid to say what you really feel, even if it's to tell them, "I'm so sorry. I don't know what to say, but I'm here for you." There is beauty in the honest confrontation of death and grief and only more hurt in the awkward avoidance of bringing it into the light.