You are about to take that first important jump in rank.  It might get you a different color helmet.  It definitely will change other things. 

You’re a good firefighter, but you’re young and will be moving up over more experienced firefighters, some of which are your friends.  There are mixed emotions.  How you respond to this is a test in your capacity for greater responsibility.  Not everyone wants promotion, and reaching a level of satisfaction is not a bad thing.  Some of your friends are content at their present level and job. 

The important and difficult part of managing your buddies is perspective and balance.  You can’t let them get away with murder on the one hand, but a domineering heavy hand is no good on the other.  Finding the balance point is easier said than done, and will take time, trial, and error.  Anyone who tells you they know exactly where that is, well, they’re lying to you.  The good guys under you will want you to succeed.  Those that don’t, and they are out there, will be easily identified.  Even though some will attempt to undermine your authority, treat them fairly.  That doesn’t mean you let them succeed with their obstructionism, but by not lowering yourself to their level, others will notice. 

Lead by example, both in the station and on the fire ground.  Show, don’t tell.  A good officer doesn’t have to talk a lot to earn respect and get others to follow.  Treat the firefighters under you the way you wanted officers to treat you. 

 At every level, somebody moves up, and others do not; it is how it is.  By now you’ve seen good, bad, and great officers.  Take the characteristics of those you like and respect, and emulate them.  As importantly, avoid those of the officers you don’t. 

Be accepting of change, but not unthinkingly.  All change isn’t bad, but it isn’t all good either.  The rookies will frustrate you at times.  Some may not progress as quickly as you think they should.  Try to learn patience.  Everyone learns in different ways and rates.  Mentoring is a long game, and sometimes goes into overtime. 

You know already that the right people don’t always get the promotions, and so does everyone else.  Putting on a new helmet doesn’t make you an officer.  Your actions and attitude do that.