Things that have helped:

Telling funny stories about my dad or making fun of him in general

Not forcing myself to believe in some sort of afterlife, and not forcing myself to not believe in one

Saying the mourners' kaddish, quietly and to myself. I don't stand up because he wasn't Jewish and it doesn't feel genuine to his memory. I have lots of thoughts about this for another post...but in general, I find some solace in Jewish rituals

Remembering that it was his choice to smoke, and also, that he was able to quit cold-turkey the second he was diagnosed

Knowing that he probably wouldn't have wanted us to watch him die. And knowing that he didn't suffer for very long

The fact that I was able to sit with him and say goodbye. I found being near his body very comforting, which is actually a relief because I was terrified before I went into the room

The Giants winning

Reading about death. How to overcome fear of death, death rituals, etc. This actually really, really helped

Listening to other peoples' stories

Beer -- not in a drinking-my-sorrows kind of way, I promise. I remain a self-preservationist to the end. But my dad loved beer.