The fact that you're aware of the devil's existence means you're already ahead of the game. One of Satan's most effective strategies is convincing the masses that he doesn't exist. But he doesn't give up just because you're a Christian. He'll put doubts and fears in your head (as well as your family members). He'll also try to break up your family, destroy friendships and cause strife at work. But you just need to see it for what is and know that you can and will overcome. Just keep reading the Word, keep praying and do your best to educate your family members about the wiles of the devil, and of course, God's plan of salvation.
"Greater is he that is in you then he that is in the world."
I John 4:4