The Bible
The best way to know God is to read His Word. Unfortunately, many Catholics rely on the readings at Mass to learn Scripture and don’t take the time to read the Bible at home.
The Catholic Bible, with 73 books, can be overwhelming, but there are many Bible studies that help you navigate Salvation History. My favorite is The Great Adventure Bible Study by Jeff Cavins. He has also written a book with Tim Gray called Walking With God that is a condensed version of the study.
Before you read Scripture, pray to the Holy Spirit for help, and spend time afterward reflecting and meditating on the Word of God.