In my opinion there are four time-honored principles for spiritual growth:
1st we study from all the best books, most importantly from the Holy Scripture. Studying from these books will help us to learn from the many different sources what our Heavenly Parents wanted us to learn from. They want us to be well-rounded and to learn all we can. They have inspired many people to write on a variety of different topic. We need to be multidimensional in our learning. We should study the teaching of all good and righteous spiritual leaders including members of our own faith. We need to study the sciences, history, etc. All good that we have around us and that includes writings, are from God. It is through Him and by Him that all that is good is available to us. So we need to learn from them so we can become like Them.
And as I said – the most important study we have to from our inspired Scriptures. There is so much to learn from them if we only take the time to study them.
2nd – Prayer is an important part of spiritual growth, prayer will allow our minds to be focused on learning from our studies. In prayer, we ask our God to help guide us in the words, thoughts, and meanings of what we are studying. We ask that we are able to understand what is being read, what is the purpose of what we are learning.
3rd – Ponder, once we start to study and pray, we need to ponder what we are studying and see how it applies to us and our lives here. We need to ponder on the mysteries of the Gospel and the mysteries of our world, and all that which is new to us. How do all these things fit together to help us and to honor our Lord?
4th – Work – We must work at what we learn and apply the knowledge gain from the study, prayer and pondering that we have done. Knowledge without applying it is useless, such as faith without works will not save us.