Prayer is one of the most spiritually fruitful ways you can support vocations among young people. Pray a Holy Hour or the Stations of the Cross specifically for vocations – links to these and prayers for priests can be found here.
Here is one prayer for vocations that everyone can pray:
God our Father, we thank You for calling men and women to serve in Your Son’s Kingdom as priests, deacons and consecrated persons. Send Your Holy Spirit to help others to respond generously and courageously to Your call. May our community of faith support vocations of sacrificial love in our youth and young adults. Through our Lord Jesus Christ, who lives and reigns with You in the unity of the Holy Spirit, God, forever and ever. Amen.