Compile a complete list of all players on the varsity team and all players who did not make the cut. If you will be making a junior-varsity team, list those players as well. Make these lists as impersonal as possible. That will remove a little of the sting for the players who didn't make the team they were aiming for.
Place a short statement at the bottom of the list that invites students to contact you with questions and concerns about the team announcement. This enables players who did not make the team to ask you about their specific performance, and it gives you the opportunity to give struggling players advice and tips for improving.
Send the team lists out by email or post the announcement on a school website. This enables students to view the rosters privately instead of in public, where they may be surrounded by peers.
Provide specific feedback to players who did not make the team, if the players request it. Use the player's performances and the data from tryouts to give the player specific areas to improve upon. For example, if the player needs to improve speed or offensive play, mention these areas. Try to be as positive and encouraging as possible to motivate the player to continue to strive to improve. Present placement on a junior-varsity team as a learning opportunity that a player can use to progress to the varsity level.