If you offer God careful and fervent prayers from a contrite and humble heart, you love yourself. If you are temperate, free from vainglory, and sober, you love yourself.
If by almsgiving to needy brethren you transfer your possession from earth to heaven, you love yourself. You make your corruptible property incorruptible, and your temporary possession eternal and inalienable.
If you are so merciful that you share the pain of all your neighbor's weaknesses and deficiencies, and renounce judging and belittling your neighbor, then you love yourself.
When you forbid yourself judgment and condemnation of your neighbor, for which you have no right, the just and merciful God removes the righteous judgment and cancels the righteous condemnation deserved by you for your many sins.
Whoever wishes to love himself properly, without being deceived and carried away by self-love, that is, by his fallen will guided by falsely named reason, must carefully study the Gospel commandments. They contain spiritual reason and lead the one who fulfills them to the perceptions of the new man.
While studying the Gospel commandments, and after studying them, one must observe the desires and inclinations of the heart with all vigilance and sobriety. With strict watchfulness, discernment of our desires and inclinations becomes possible for us. Through habit and the fear of God, this discernment becomes almost a natural exercise.
Not only every desire and inclination plainly contrary to the Gospel commandments must be rejected, but also all desires and inclinations that disturb the peace of the heart. Everything that flows from the divine will is accompanied by holy peace, according to the experiential teaching of the holy fathers. By contrast, everything accompanied by disturbance has sin as its beginning, even if outwardly it seems to be the highest good.
Venerable Macarius the Great teaches this in Homily 4, chapter 13.