Hinayaana is the logical development of the principles of the Paali canon. The Abhidharma is the systematization of the views expressed in the canon and Milindapanha.
The fundamental doctrine is that all things are momentary. All beings consist of momentary entities called dharmas. It is phenomenalism arguing against the existence of substance. There's no thinker, only thoughts; no feeler, only feelings.
The goal of existence is Nirvaana or the cessation of consciousness. There's no speculation about the condition after Nirvaana.
The arhat ideal is the distinguishing mark of Hinayaana, which believes in the possibility of emancipation through one's own powers. The method is contemplation and meditation on the four noble truths. Arhathood is esoteric and the Hinayaana doesn't confirm the attainment of Buddhahood by every creature.
The Buddha though deified, is revered simply as a teacher. He is neither divine nor supernatural. He is different from the other saints who attained bodhi, because he proclaimed the truth of salvation to the world.
Social life is discouraged and asceticism glorified. Married life should be avoided as if it were a burning pit of live-coals.
Vaibhaashika and Sautraantika are the two schools of pluralistic realism (Sarvaastivaada) in Hinayaana. Most of the Sarvaastivaadin works are in Sanskrit.