John Kleinig inGrace Upon Grace: Spirituality for Today understands that the doctrine of the priesthood of all believers is carried out in VOCATION:
“There are two hidden sides to our secret vocation. First, we stand in for others before God the Father together with Christ. We represent them before the Father by identifying with them and their needs and by praying for them.” (Page 64)
“Second, as holy priests we take God and His blessings with us to every person that we meet. We are, if you like, ‘christophers,’ carriers of Christ, bearers of Him to others.” (Page 65)
“These two sides to our priestly vocation interact and enrich each other. By bringing others to God the Father in prayer, we are equipped to bring His blessing to them as we go about our business. As we engage with people in our work and leisure, we discover their needs and so are prompted to help them by praying for them. Thus we serve as secret agents, priestly people who lead heavenly lives on earth by remaining in touch daily and weekly with our heavenly Father.” (Page 65)
This puts forward a simple spiritual exercise: When you interact with people in your calling–on the job, in your family, in your citizenship (as you read the newspaper, for example)–and become aware of their needs, pray for them. Intercede for them. Be their priest.