"So Jesus called them and said to them, ‘You know that among the Gentiles those whom they recognize as their rulers lord it over them, and their great ones are tyrants over them. But it is not so among you; but whoever wishes to become great among you must be your servant, and whoever wishes to be first among you must be slave of all. For the Son of Man came not to be served but to serve, and to give his life a ransom for many’" (Mark 10:42-45).
At this point in Mark's telling of the story, Jesus and his 12 disciples are heading for Jerusalem for what will be the final days of his earthly ministry. James and John, disciples and brothers, seem to realize that things are about to change, and they decide to make sure that they will be prominent in the new kingdom that they believe Jesus will establish. They ask him to promise that they will be seated at his right and left hand. Jesus explains, basically, that it's not that kind of kingdom, and he cannot make that promise. When the other disciples hear of it, they are highly indignant against James and John.
It's at this point that Jesus calls the 12 together and offers the explanation quoted in the passage. The hierarchical power structures with which they are very familiar, both in government and religion, will not be a part of the kingdom of heaven—the new spiritual consciousness that he has been teaching. The Christ Consciousness—symbolized as the Son of Man, the realization of our oneness with the Divine—is not about personal gain. It will only be realized in giving, not in accumulating. It is about being of service to others and making choices out of that energy of love. To answer your question, I would say that the "attitude of the servant leader" is simply love.