My immediate response here is if there is such a thing as self-love, as in, a completely, self-serving, self-centered, selfish activity as loving just yourself, isn’t that a pretty narcissistic activity to be engrossed with? Not one bit, when you realize that you are the universe. So the self, being the universe, you are a physical manifestation of this vibrational universe. You are whole and complete and yet a part of the whole, when in vibrational harmony with the universe (the self). This means having to be positive, in order to be in positive vibrational harmony. And when you realize this you will automatically be loving yourself. The opposite (which is negativity) is in vibrational disharmony where you are serving/loving nothing.
To return to your question, I’d love to approach this question with the question, how do you practice self-love? Or maybe what is self-love, a question more appropriate. Simply because if you know what is self-love, more succinctly, if you have “realized” self-love, then you know that it is a state of being, “a positive state of being”. You cannot become positive by loving “you”.
You are part of the whole. The whole being the entire universe and all of what is in it. When you can love everything and everyone everywhere and at all times you are in a “state of being” “love”. When you are love you will be loving yourself. “Love” the way we experience it is believed to be the expression of an emotion like anger or happiness etc. However, that is not the case, for love is the very essence of you. So loving yourself, or self-love is about loving, everything, everyone, everywhere, all the time, not an expression of love but experiencing in your thoughts, “love”.