Faith, the theological virtue, along with hope and charity, is not infused into everyone. It is granted when the Holy Spirit is granted (in your Baptism, Confirmation, Eucharist, Reconciliation - granted by the priest / bishop).
Faith, thus granted, is a part of “Sanctifying Grace”, where God gives to you (with the indwelling Holy Spirit) what you need to be Good and Do Good (and thus be suitable to be in the presence of God, for “you must be perfect as your Heavenly Father is perfect”.
Faith is a virtue, a supernatural virtue, only present in the friends of God in whom the Spirit dwells, as in a temple. Where there is no friendship and love of God, there is no faith.
As a virtue, Faith is a “Habit” - it is a “knowing how and what to do” in situations where a person is resolved “I am going to do this thing virtuously”, with a glint of happiness in his eye. The glint of happiness is knowing that he is a son of his Father, and a brother of his Lord, with the same Spirit of Love which they both breathe out to him.
We can do everything we do every day virtuously, because of this Grace that infuses every bit of our soul, as our soul infuses every bit of our bodies. We are his sons and daughters, with the guarantee of our life in Him, which guarantee is the Holy Spirit.
Faith, along with the other virtues of Sanctifying Grace is present wherever his Spirit resides. And his Spirit is given in Baptism, sealing you as his own, as a citizen of the Kingdom he established with the Baptism of Jesus as the King of this Kingdom. Are you Baptized? You are a citizen of this Kingdom, of which Jesus is the Lord, the King, and you were marked with the mark of citizenship, just as you carry your social security card as a mark of US Citizenship (if you live in the US).
Where is the effort? The effort is that what God saw we needed was not “fixing us to be unable to sin”. His idea of what we needed was virtues, habits, where we would have the “tools” to be like Him, doing good through our wills, rather than doing good without knowing that we were willing something difficult. So, now, knowing we are his children, alive, and knowing we have virtues, habits of Faith, Hope, Charity, knowing this we can take it seriously and conclude within ourselves, “I am going to drive virtuously”, “I am going to talk with my wife virtuously”, “I am going to eat this meal virtuously”, “I am going to worship at Mass virtuously”, “I am going to walk my dog virtuously”, “I am going to play with my daughter virtuously”, “I am going to pray this morning virtuously”, “I am going to treat my co-worker virtuously”, “I am going to shop virtuously in this store”, etc. - every doing that we are about to do, we can look at and conclude (because of who we are as our Father’s children) - we can conclude, “I am going to do this virtuously”, with a sparkle in the eye, the sparkle of gladness.
When you do this, appetites get suppressed, which is the work, the effort. You see something appetizing and your feet turn slightly in that direction, preparing you to grab at the thing. Then, because you knew you were going to do your doing virtuously, your feet begin to turn away from the “treat”, and you walk on by, with a touch of sadness - your appetite is crying.