1. Impress upon witnesses that "worldly people" (such a strange tag) are just like them. That you have met many honest loving kind good decent people that have never heard of Jehovah's Witnesses. This will not shake them up completely, but will plant a seed for them to think about. Give good experiences of volunteering with non witness groups. Good news that you have read. This can break down the us them mentality.
2. Emphasize that you have not changed completely, but in fact have changed very little. My mother says things like "you aren't the person you used to be." I tell her, yes I am, I still have a sense of humor, I still love all the things I've always loved, I'm still honest, caring and a hard worker on my job.
These ideas go right towards breaking down the wall they have built around themselves.