One of the biggest problems is the spreading of lies and misinformation that keeps getting spread by others outside the Catholic Church. This problem has been going on for a long time and is still happening. I see this all the time on Facebook by family members as well as others. I generally will find something on Catholic Answers and post it on Facebook. I can remember back in 1996 having to correct people I worked with, because they were spreading misinformation.
I would strongly suggest buying a good Catholic Study Bible and books on Catholic Apologetics. There will be some ads below where you can purchase these items to build up your library. It is up to us to spread the truth about the Catholic Church and in the process others will convert to the Catholic Faith as they come to understand the the Catholic Church is the true Church started by Jesus Christ.