Sacrifice beads were part of the life of St. Therese of Lisieux who spent her life making presents for God by trying to please God every minute of every day. They contributed to the formation of her "little way", the path to holiness that she found for herself and many others.
When Therese was a small child, her older sister, Marie gave her a special string of beads on which to count her presents for God throughout the day. When she did something to please God, she would pull a bead on the string. At the end of the day she would count her presents to God, offering them to Him as a part of her night prayers. The "presents" could be any act of kindness or unselfishness toward another, or any time that kindness or charity was chosen over selfishness, in word or deed.
This simple string of beads can serve as a tangible reminder to you of the opportunities that you are given each day to please God, a concrete way to be accountable for your actions (or inaction), and an opportunity to challenge yourself to grow in holiness each day. Like St. Therese, you can try to do better every day, pleasing God with small gifts whatever your day may bring.
Like any virtue, it takes practice to master, so don't be discouraged if you are unable to pull many beads at first. As your awareness increases, you will find more and more opportunities in your day for these little acts of holiness. Stick with it for a while, and you will be surprised by how much joy you will find in these little acts of kindness for God.