i don't typically cry. People who I've talked to in the past, friends, counselors, etc, have said that I don't cry enough; but they also don't pressure me to do it. It's more of a passing comment.
That said, there are times when I do. Very weepy days. Not huge, full on, my trauma was so horrible and I'm so horrible for having it happen to me sobs. I call those weepy spells "my eyes are leaking". Because that's how it feels. They just drip. Slowly, constantly, most of the day.
Crying can help. I do find that, sometimes, and it's an awesome release for some of the pain. Healthier, certainly, than my dissociation. Your experience may be different. This is what I like to tell myself, and it's a great way to explain it people whether in more casual settings or in therapy. "I can laugh or I can cry. I can find the humor, black as it is, or I can drown in the pain of it, because if I start crying I will never stop."
As far as crying for dummies? I have a couple book series, couple of chapters in each that always tear me up. On a day when I think I'll benefit from letting my eyes leak a bit, I go back and reread those books. But forcing it to make someone else feel that you're having a "better" therapeutic experience? Don't.