Being raised LDS, and developing an 'allergy' to it and similar institutions at an early age, I didn't have any contact with Ash Wednesday until well into adulthood. My first encounter with it was actually T. S. Eliot's poem by that name. It has since been inextricably linked in my mind to that poem, and to poetry. For a number of years I would raise a glass to my favorite poets and read them out loud on this day. And, after all these years and after having become a priest, that still seems appropriate. For what is Ash Wednesday but the beginning of Lent? Which is traditionally a time of redirection, of reducing worldly attachment and redirecting that time or energy into the spiritual life. An attempt to live more poetically, as it were.
As Gnostics, we use the Lenten season for a conscious redirection. The world isn't likely to let us go long without asserting its priorities on us, while what transcends the world requires our efforts to remain a part of our lives. Use Lent to seek balance. Fast from what is “too much” and redirect that time and energy into what “is not enough.” The form of this varies from individual to individual, but the intent, and indeed the sacrifice, is the same.
This is not merely personal balance either. We don't get off so lightly as that. To sacrifice in a conscious sense is to make sacred in a living sense. An important part of that balance is to sacrifice some of our unconscious or unhelpful behaviors that trap us within ourselves and our habits and redirect that energy and time towards becoming in a small and yet real way, a secret agent of God where you hadn't been before. We fast from what consumes us, and symbolically, that which we needlessly consume. Whatever that may be, and to whatever extent and form that may take, is a matter of personal discernment.
The guidelines I would suggest come from the gospel of Thomas: do not lie, and do not do what you hate. Keep in mind the true focus, the 'making sacred' part of sacrifice. That is the important part, the rest is just a tool to accomplish that. Challenge yourself, but don't go against yourself. Keep it small, real, and conscious. Also, "fasting" doesn't necessarily mean eliminating, it means consciously limiting (or, limiting to make conscious). For example, an individual may choose to fast from television or Internet time, as well as, chocolate or eating out; then use the time from the former to volunteer and to pray, and the money saved from the latter to donate and to create.
Remember, O Soul, thy body is dust and to dust it shall return. Remember. Refocus. Redirect. All that you see around you shall pass away, yet there is that which cannot be lost even in the deepest depths of darkness—for it shines, and the darkness cannot grasp it. Our root, our anchor, our home, and our hope lay beyond all that which screams demanding our attention for its whisper is enough, if we are still enough to listen.
What we do in the world to improve things in the world is not meaningless nor worthless, yet it is always severely limited, while in our truest nature we are not. An ash cross on the forehead calls us back to the perspective of Gnosis, to refocus, to redirect ourselves in our actions so that we may bring this sacred truth more fully into our lives.