Spiritual growth happens when we obey God. In the Old Testament, God commanded his people to obey his commands, to "walk in" them. Walking in God's commands is a way of saying that your whole life is characterized by obedience to God.
The Hebrew word for "walking" is halakah. Jewish teachers came to use this term to describe a life of obedience. The halakah was a life lived in obedience to God's commands, and therefore it was the best life that one could find.
For some reason, we Protestants (Evangelicals particularly) don't often think that obedience is a necessary component to a spiritually healthy and vibrant life. Maybe it's the ideal of American individualism, or postmodern anti-authoritarianism, or a misunderstanding of salvation by grace alone, but we just don't think about obedience. We don't have a well-defined halakah.
But I can't think of any better way to grow spiritually than to obey God. Obedience often demands that we risk a step of faith or that we die to ourselves in some way. Obedience is active faith, and any time we take a step of faith, we walk with God.
If you're frustrated with where you're at spiritually, and you feel like you're not growing, it's probably because you're refusing to do something God is telling you to do. You need to take that step. You need to do that thing God is urging you to do. Only when you step out in obedience, when you live the halakah life, will you begin to see the transformation of character you're longing for.