A lot of people don't realize how spiritual teachings can be of value to them. The answer is a short one = PSYCHO-PHYSIOLOGY. But, for one to understand it, or to be able to put it into practice, one must understand that the psyche is as real as the physical body. Thoughts are things, emotions are things, and therefore are real. Thoughts and emotions don't impact the senses but they do impact the sense centres of our brains. A thought about an apple can trigger the same visual response as the sight of a real physical apple in the sight centre (as proven by actual experiments using an MRI or fMRI machine). The same is true of sound, smell, taste and touch. Basically, we can think (meditate) reality into our perception. And, it also applies with emotions. This can be through a great amount of instantaneous energy interaction (great fear or love), or done repetitively over a long enough period of time. It works with both positive and negative energies.

So, what has any of the above to do with spirituality?

It means that we can manifest it into objective reality.

How?

Spiritual <-> Mind <-> Psycho-Physiological <-> Physiological (Physical) <-> Material.

In short form, spirituality is about the realisation of the unity and harmony of life. Spiritual activity is about unfolding the power of freedom achieved by that realisation of unity and harmony.
First, we take the above information and turn it into knowledge. That is, we find ways of how we can give it significance and utility in our lives. Then, we turn it into wisdom. That is, we apply ourselves through discipline until it become an intrinsic part of us (our beings). This should follow the path of 'practice makes perfect'.
The practices we perform are best when they include all aspects of our lives. By that, I mean the mental, emotional and physical. Activities such as prayer and meditation are good. But they would be better if they are accompanied by practices such as physical exercises (yoga, sports or games, etc) and also when we're involved in activities that allow us to interact emotionally. In this way, we become fully engaged. (For example, the monks and yogis are known to visit people every once in a while and engage with them not just in spiritual or religious practices but also in the day to day activities of those common folk. They even play games and such.)
Influence of the body by the mind and emotions has been proven true scientifically because those who study the psyche have realised that thoughts and emotions do affect our body chemistry, perhaps through our bio-energies (bio-electromagnetic and such). And, in turn, we influence our material environment and, through that, other living beings.

So, what happens when we don't perfect our practices?

We end up with the kind of stupid bias and inflexibility that we observe in religions. We end up with the kind of separateness (an exclusivity that excludes oneself), suspicion, incredulity and complacency that we observe in the current fields of knowledge.

Can we be like former philosophers (Pythagoras, Socrates, Plato, Aristotle, etc) who embraced all knowledge that life had to offer without diminishing their intellect, their emotional capacity or their participation in this material world?