Saint Theophan gives us clear advice about how to make proper use of our conscience.
"Just keep this law: Never do anything, whether great or small, that goes against the conscience. If you do violate this, compensate the conscience at once through your own inner repentance at home. Confess it to the priest later. The conscience is a great thing. It is the voice of the Omnipresent God in the soul. He who is in the world with the conscience is also in the world with God."This seems so logical and seems like it should be easy. But, first, we must become continually in tune with our conscience and be able to recognize when we are going against it. This requires some degree of spiritual maturity. Most of us have lived lives where we have habitually ignored our conscience for one reason or another. We have become insensitive to its call and no longer hear it very clearly. Even when we do, it has become an easy thing to ignore it.
Saint Paul tells us, those who are justified are those "who show the work of the law written in their hearts, their conscience also bearing witness, and between themselves their thoughts accusing or else excusing them." (Rom 2:15)
As you adopt an Orthodox way of life, with daily prayer, fasting, regular participation in worship services and sacraments, reading Scripture and the lives of the saints daily, you will quite naturally find the voice of your conscience getting louder and louder. Then, you can take the next step and make a commitment to follow it no matter what. When unsure of action talk with your spiritual father as we can be misled when our faith is immature.
When you cannot muster the discipline to act on this inner voice, do as Saint Theophan says, "compensate the conscience at once through your own inner repentance at home. Confess it to the priest later." Shortly you will find your ability to abide by your conscience increases dramatically.
Saint Paul says,
"And in this do I always exercise myself, to have a conscience clear of offense towards God andtowards men."
Reference: The Spiritual Life, p 277