Tentatively, it might work to teach rational methods of improving one's life in small ways with a gradual spread into more areas rather than starting with the idea of becoming rational about everything. That might attract people who are dubious about rationality (without knowing what it is) and/or don't want sweeping self-improvement.

I didn't think of it this way. I agree. (Also, is it considered superfluous in this community to comment only for the sake of agreeing with someone? That's conceivable to me.)