Teaching a class on Dialogue with Asian Religions, I noticed a lot of the advice related to inter-religious (or interfaith) dialogue is related to the advice that Dale Carnegie gave to people in “How to Win Friends and Influence People” published back in 1937.
This slide presentation deals with some beliefs that Evangelical Christians have as to how to influence and communicate with people of other religions. Much of these beliefs lead to counterproductive results. The presentation looks over some such beliefs, then connects some of the answers with one of the chapters from Dale Carnegie’s book.
If you feel that it is inappropriate to get religious advice from a self-help book, I am sympathetic to your concern. But I might still suggest that you look at the presentation. Then consider reading Carnegie’s book (it is actually on free download online in .pdf). A lot of it is quite relevant in Inter-religious Dialogue.