How does one get around the egocentric pitfall of "looking down on", being prejudiced about, or "putting down" another person's religion because one feels that they possess the truth about who God is and the other person's religion is wrong?

The same way as you would normally deal with derogatory statements and actions.

Tell me a couple of their statements, and I will tell you something to say in return.

Compassion is something that is missing from most people these days. Simply put, most people lack tact... which is where most of the problems come from.

This is not just a problem in Christianity either...

How does one get around the egocentric pitfall of "looking down on", being prejudiced about, or "putting down" another person's religion because one feels that they possess the truth about who God is and the other person's religion is wrong?
Well, I suppose that you would have to shed your human nature to avoid it altogether. But, until that happens, I suggest mixing 1 part humility with 1 part compassion with a measure of humor to top it all off. Seriously.

Peace...

How does one get around the egocentric pitfall of "looking down on", being prejudiced about, or "putting down" another person's religion because one feels that they possess the truth about who God is and the other person's religion is wrong?

Love them.

(Advice I often fail to carry out myself, but keep trying).