As you know you should read your Bible and pray every single day there are some added materials that will help your spiritual growth.
Although written almost 15 years ago, Pastor Chuck Smith's recommended reading and reference classics list is a great starter:
Strong's Exhaustive Concordance Of The Bible by James Strong
Vine's Complete Expository Dictionary Of Old And New Testament Words by Vine, Unger, and White Jr.
Halley's Bible Handbook by Dr. Henry Halley
The Pilgrim's Progress by John Bunyan
Foxe's Book Of Martyrs by John Foxe
Morning And Evening by Charles Spurgeon
The Pursuit Of God by A.W. Tozer
My Utmost For His Highest by Oswald Chambers
And a great small book on prayer called Power Through Prayer by E.M. Bounds is another Chuck favorite.
Additionally devotionals Daily With The King by W. Glyn Evans and any of the Jon Courson devotionals are filled with great spiritual nuggets and insights.