In the introduction to his spiritual maxims, Brother Lawrence writes: "All things are possible to him who believes, more to him who hopes, still more to him who loves and most of all to him who perseveres in the practice of these three virtues..."
The "trick", so to speak, is not just practicing those virtues but practicing them continually, especially when it is difficult to do so. In the "Hail Mary" prayer, we ask Mary to intercede for us "at the hour of death". We ask to persevere to the very end, to keep our faith, hope, and love alive in the very moment of death, when Satan wants to cause us to falter irreparably. Perseverance is the practice of virtue when it is inconvenient, difficult, dangerous, or painful.
Perseverance is faith to the end. It is hope to the end. And it is love to the end.
How can we hope to do this? The Catechism tells us that "to live, grow, and persevere in the faith until the end we must nourish it with the word of God" . Where do we find the word of God so we can be nourished and persevere? Sacred Scripture is the written word of God. Sacred Tradition - the teaching of the Church - is the word of God passed on orally from the apostles through their successors.
Most importantly, Christ is the Word of God made flesh (John 1:1-5). He is the living water that fills and satisfies us (John 4:10). We receive Christ - we are both literally and spiritually nourished by His Body and Blood - in the Eucharist.
How do we persevere? By learning and living the faith handed down through Christ's Church, keeping 100% faithful to the Church He established. By studying and praying God's written word in the Bible. And most especially by receiving His Body and Blood in the Eucharist.