I used to be a passive atheist but now I am a very militant one.
The most important and lasting way to be a good atheist/agnostic is to set an example of being a good human being, without the need for a gods instructions. That undermines the theist mind set more than anything else you can do. But congrats. on being militant, atheism needs militants and passives both.
I used to be a militant atheist, now I am a passive one.