I struggle with this as well! I am the only one of four children still in the Catholic Church, and I seriously considered leaving twice in my lifetime, before God answered my prayer to “show me where you want me to be!” Boy, did He, but that’s another story!
When I first became on fire about my faith, I wanted everyone to know the Truth (as we all do) but sometimes got too defensive about it, sometimes too self-righteous (forgetting it wasn’t that long ago that I didn’t “get it” either). Sometimes I still feel the hair on my neck raising…
Now I try a softer approach. I don’t water anything down. When my sister visits, my family still prays together and asks for the prayers of the saints, etc. I can tell when she’s uncomfortable or doesn’t want to participate, but we forge ahead anyway. If she asks a question, I start off by trying to answer it in a more personal tone instead of showing her where the teaching is in the bible or catechism. If she’s genuinely interested after my personal approach, then I back it up with the Scriptures and catechism.
Example:
She says “I don’t understand why you pray to the saints. We can just go directly to Jesus.”
I say “Wow, if there’s one thing I’ve learned over the past four years in dealing with chronic illness, it’s that I rely on the prayers of other people. I know you and your family have been praying for me, and you’ve asked others to pray for me as well. I believe in the power of prayer to get me through. It’s the same for me when I ask our brothers and sisters in heaven to pray for me. We are still family, still connected just separated by the thin veil between heaven and earth. They are right there in the presence of Jesus and want nothing more than to see all of us join them in heaven. So I ask them to pray for me just as I ask you. I figure I need all the prayer I can get!”
She didn’t have a comeback for that. Partly because I made it personal – how I feel about my faith and how I approach it. It’s harder for people to attack you personally than it is to attack the Church as an institution (sometimes Whom they see as an enemy).