St. Catherine of Siena speaks these seemingly simple words to help us on our way to salvation:
You see this gentle loving Word born in a stable while Mary was on a journey,
to show you pilgrims how you should be constantly born anew in the stable of
self-knowledge, where by grace you will find me born in your soul. ( Dialogue
It's not easy to practice self-knowledge.
I've had to face many facts in my life; sometimes those facts are not the most pleasant to contend with, but they are, however, true regardless of how painful they may be to address.
Self-knowledge doesn't only bring us to what is distressing -- that's important and necessary to realize. The good we find in ourselves we must continue to bring to perfection; the flaws, we must work to eradicate and turn into virtue.
Unless we clearly know who we are in relation to our Creator, respecting how we are made in His image and likeness, and continuing to improve ourselves to be perfect, as our heavenly Father is perfect (cf. Mt 5:48), we risk losing our own heavenly reward.
Practice the presence of God -- place yourself there often
Make a daily resolution to work on an area of needed perfection
Examine your conscience, once or twice daily
Make a firm commitment via the Act of Contrition to work on self-knowledge and improvement
Frequent the Sacraments