The apostles said to the Lord "Lord, increase our faith". (Luke 17:5)
There are many occasions when Jesus rebukes the disciples for their lack of faith. At the stilling of the storm, for example, when they wake him in the boat - "O men of little faith" he says. He remarks on their lack of faith too, when, after the transfiguration unable to heal the epileptic boy - and then, the father of the boy says "I have faith, help me where faith falls short!"
There are two interesting and important points here.
Firstly, in asking this question, the apostles see one thing very clearly. For their faith to increase - well that must be an act, or gift, or rather grace of God, not something they can do simply by their own efforts. We might think that if only we believed more, prayed harder, said more rosaries or attended more masses, then we would have more faith - but no. We can stand in the way of faith, but fundamentally faith is a gift of God, not an achievement of humanity.
And secondly, the question and its answer also reveal that faith is not simply something you've got or you haven't got. It comes in degrees: you might certainly have none, but you could just as easily have a lot or a little. (To put it in very modern terms, it is analogue, not digital). Some people have more than others, and some wish they had more. And who has more or less is not really ours to judge and decide. We should never feel guilty or inadequate if others seem to have more faith or be more devout than us - and we should never ever feel superior if others seem to have less.
So what can we do? The answer is beautiful in all its simplicity. Do your duty. Perform your service of God. Do not feel inferior or superior. Just do what you know to be right. Offer him your worship and show love and compassion to all people. Love God and love your neighbour. No more and no less is required.