ואהבת לרעך כמוך - Love your friend as you love YOURSELF. One famous Tzadik was shocked with the notion that one should love HIMSELF. Of course it makes sense that you love your friend but how can one be a narcissistic self-lover?
So he explained that ideally one shouldn't love oneself but just as we all work hard to justify our behaviors, to keep a clean reputation, to have our needs fulfilled etc. etc., so we should be as vigilant when it comes to our fellow. [For many poskim the mitzva is to act in loving ways - see here].
But I believe that the Torah really wants us to love ourselves [although one must be careful of unhealthy narcissism - and that is what the aforementioned tzadik was concerned with]. "Love" is a quality. A loving person is in love with himself, with everybody around him and with life in general. It is VERY RARE to meet such a person but they exist. Healthy self-love and otherly-love are not contradictory but complementary. The very same quality that generates love of self will also generate love of all things.
The root is the knowledge that the source of all existence is Hashem Yisborach. Once one realizes and internalizes this then it becomes easy to love and appreciate all beings - each on their own level.
One has to work on developing his/her "love muscles". It is an art and hard work.
Here is a powerful passage from a קדוש עליון:
אני אוהב את הכל. איני יכול שלא לאהוב את כל הבריות, את כל העמים. רוצה אני בכל מעמקי לב בתפארת הכל, בתקנת הכל. אהבתי לישראל היא יותר נלהבה. יותר עמוקה, אבל החפץ הפנימי מתפשט הוא בעזוז אהבתו על הכל ממש. אין לי כל צורך לכוף את רגש אהבה זה, הוא נובע ישר מעומק הקודש של החכמה של הנשמה האלהית.