The Sefer Hachinuch (Mitzva 243) writes that "Loving your fellow as Yourself is a great general rule in the Torah" because many mitzvot are dependent on it. Someone who truly loves someone else as himself would never steal from him, sleep with his wife, cheat him monetarily, encroach on his boundaries, or do anything to harm him.
So, to answer the question. According to the Chinuch, "Loving your fellow as yoursef" is the Klal (the General Commamdment) and all the other Mitzvos between a man and his friend are the Pratim (the specific examples(?) of this general rule).
Perhaps this is why Ben Nanas, when asked to find a verse which encapsulated (Kolel) the most of Torah, chose this verse. (Midrash brought by Yaakov ibn Chaviv in the introduction to his Ein Yaakov - See curriculum to this shiur for an english translation)
Follow these links to some different approaches to understanding Rashi on Kedoshim 19:18:
"You shall love your fellow[-Jew] as yourself. Said Rabbi Akiva: This is a great principle in the Torah."