How Do We Mature as Believers?

So, how can we grow? How can we mature as believers? How can we demonstrate that we have real spiritual life and are growing in that life?

The author of Hebrews describes the immature as those who are "unskilled in the word of righteousness." He then says, "Solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good and evil."