When we last left Moses he had fled Egypt a wanted man, rejected by the very people he was called to deliver, and probably confused as to his calling.  It is good to remember that man does not have the means to train himself to be used of God; it is a supernatural act, accomplished only through the Holy Spirit.  Jesus made this point well in addressing who is fit for kingdom living, pointing out it is impossible in the natural:

With men [it is] impossible, but not with God; for all things are possible with God.  (Mark 10:27, Amplified) 

Beginning in Exodus 2:16 we catch a glimpse of Moses’ wilderness training.  It is detailed for in this section of the narrative that Moses is used of God to help the priest of Midian’s daughters at the well he just happened upon (Exodus 2:16-20).  His actions were more than a kind deed, it was training.  Moses already had proved he had the heart for leadership, but now he gets to use it, though on a much smaller scale than he had hoped: to deliver the daughters from the shepherds who caused trouble for them.  Moses had to learn to be faithful in the small things, growing dependent on the Lord moment by moment, step by step.  Before the big things can be accomplished we must be tested on a smaller stage:

His master said to him, Well done, you upright (honorable, admirable) and faithful servant!  You have been faithful and trustworthy over a little; I will put you in charge of much.  Enter into and share the joy (the delight, the blessedness) which your master enjoys.  (Matthew 25:21, Amplified)

This is a very important concept to grasp.  When the Christ was training the Twelve He gave them opportunity to practice ministry before the Commission came after His resurrection.  This concept is seen again in what follows with Moses’ preparation time:

Then Moses was content to live with the man (the priest of Midian), and he gave Zipporah his daughter to Moses.  And she bore him a son.  He called his name him Gershom, for he said, “I have been a stranger in a foreign land.”  (Exodus 2:21-22, NKJV) 

Moses was content. Content in the Hebrew means to choose to do something.  The focus of this verb is on the decision to act.  This concept is expressed on three levels.  On the first level, the individual shows a willingness to act a certain way, to accept an invitation.  On the next level, the individual is more active and voluntarily decides to act a certain way.  On the final level, the individual is even more active and voluntarily decides to act a certain way with determination and resolve.  The use of this word implies the process by which Moses came to stay with the priest of Midian.  As Paul points out there is a principle to be learned: 

[And it is, indeed, a source of immense profit, for] godliness accompanied with contentment [that contentment which is a sense of inward sufficiency] is great and abundant gain.  (1 Timothy 6:6, Amplified)

…to live with the man.  Moses in essence is called by a man of God to live with him, and to learn from him in day to day life.  Moses, who failed in Egypt despite his position, accepts the job of apprentice of a priest of God.  It is assumed that training takes place as we learn more about this relationship when Moses delivers the nation from Egypt and the advice his father-in-law will give the leader at that time.

He called his name Gershom.  Moses comes to recognize his true position: a stranger in a foreign land.  With Moses now being developed into becoming poor in spirit his training has started.  Moses had to rid himself of worldly position and rely on God and God alone.  In Exodus Chapter Three we will see that Moses became a shepherd during this time, a position that was near the low end of the social economic ladder of the day in the culture of the time.  But it is a good place to be as we will soon find out.  Moses can now become the man he was destined to be: a man poor in spirit.

Use the template that Moses used to become poor in spirit.  Implement the main points above into your life today.