To contemplate Ash Wednesday and the beginning of Lent, those sobering words accompanying the imposition of ashes are a good place to start. (More personally, “you are dust, and to dust you shall return”!)
This is called a memento mori, a reminder that you are going to die. How can it be helpful to meditate on that unpleasant fact? How can that change your perspective on things? What does that have to do with Lent?