Critical thinking is necessary, but that's not really something we socialists have any power over in the broad populace. It's largely a product of education, combined with the lessons being in a given class teaches us. I try to do my best to explain that I want a better world, but that also requires being honest and forthright with me being a communist, and explaining exactly what that means and why.
As for Marxism-Leninism, I'd argue its controversy mostly stems from it being the branch with the most actual existence in the real world. Bridging the gap to other socialists, for me, involves demystifying it and trying to explain the basics of it theoretically. I try to explain what I can, where and when I can, and that has seen a good deal of success.