I think religious people follow a preset dogma. They never stop to think of the consequences of their actions and beliefs. They just do what their religious leader tells them to do and think.
Spiritual people appreciate the natural world and attempt to not only understand why things are as they are, but also to live in harmony with the world and things that are "greater" than themselves.
A spiritual person looks as the stars in awe and exclaims over their beauty and power. A religionist looks at the stars and sees only a god that "created" these things for his own purposes. A religionist thinks that God created the universe so he would "not be alone".
The spiritualist sees the universe as an equal part of the universe. The religionist sees the universe as their master's playground with only his selfish purposes in mind.
The spiritualist sees humanity as a beautiful addition to the universe. A religionist sees humanity as an imperfect child that must be taught, sometimes very cruelly, by a "loving" parent/god
Religionists cannot face themselves in the mirror without the hope of "salvation". Spiritualists know that they are already inherently good.
Personally, I think that religionists are genetically imperfect. That they lack some piece of the DNA puzzle that gives them better reasoning ability. I have hopes that someday, all humans will evolve to the point of spirituality over religion.