Start with an email:
   Dear student leads,
   As you are all in leadership positions, one of your goals this year should be to learn and practice leadership skills.  I'll periodically send emails like this focusing on a specific skill. 
   Leaders make decisions.  Choosing the right style for each decision is important and will significantly impact your ability to lead effectively.  Please read this brief summary of the 4 primary decision styles:
       https://www.zingtrain.com/content/decisions-part-one-choosing-decision-style
   As you approach each decision over the next several weeks, think about which style to choose and at some point we'll discuss what worked well, what didn't, and why.
   Good luck and have fun!

Follow up with a 15-minute discussion(s): 
   * Ask about decisions they've made, which style(s) they used, why they were appropriate (or not) for the issue at hand.  Discuss decisions you have made.
   * Key points to emphasize:
      * Build consensus wherever possible - team members are more committed when they feel ownership in the decision.
      * Be consultative if you can't build consensus - team members will still feel good about a decision, even if they disagree with it as long as they feel their wishes have been heard and given fair and careful consideration.
      * Make command decisions only when necessary - there is a cost to each command decision: make them only if time does not permit the other styles