Shia are muslims that follow holy prophet (pbuh &hf)  and his family ( 12 imams that called ahl albayt) ; as a true sunnah of the prophet of islam . But sunnis follow sahaba instead of ahl ulbayt. Following of ahl ulbayt confirmed and ordered by the Rasul Allah (apostle of Allah) many times. The book of ahl ussunah specified major of them:

The Messenger of Allah said:

"Whosoever wishes to live and die like me and enter that heaven (after
death), which my lord has promised me, namely, the ever lasting heaven
should acknowledge Ali (AS) as his patron after me, and after him he
should acknowledge the sons of Ali, because they are the people who
will never leave you outside the door of guidance nor will they
let you enter the door of misguidance."

Sunni references:
- Kanz al-Ummal, by al-Muttaqi al-Hindi, v6, p155, Tradition #2578
- Also abridged Kanz al-Ummal on the marggin of Musnad of Ahmad Ibn Hanbal v5,
p32

Again the significance of leadership of Ahlul-Bayt has been confirmed by the
following beautiful analogy of the messenger of Allah:

The Messenger of Allah said: "Regard the Ahlul-Bayt among you as the
head to the body, or the eyes to the face, for the face is only guided
by the eyes."

Sunni references:
- Is'af al-Raghibeen, by al-Saban
- al-Sharaf al-Mua'abbad, by Shaikh Yusuff al-Nabahani, p31, by more than one
authority

Also:

The Messenger of Allah said: "My Ahlul-Bayt are the protected place of
refuge about the dispute in religion." (Mustadrak Hakim)
 

and  many other hadiths are in sunni scholars' book .

Hadith thaqalayn (thaghalain) is one of them that holy prophet Muhammad ordered to follow Quran and Ahl ulbayt.

You will find more about shia and sunni beliefs at:

Islamic Encyclopedia

and read more about sunni and shia differences and commons :

The Right Path

Pishawar Nights

Introducing the Ahlul Bayt Find out who the members of the Prophet's Household are and why they are special. Unity between Shi'a and Sunni United they stand! Discover the common basis that allows unity between these branches of Islam. Shi'i Beliefs Explained Rational, well-evidenced, but sometimes misunderstood; the Shi'a explain their beliefs. Debates and Discussions Polite, logical, fiery, passionate; they are all here!   Responses to Misconceptions Often the victims of ignorant or malignant propaganda, the Shi'a respond with their defence. Why they became Shi'a Find out more about those who decide to become Shi'a and what motivates them to do so. Resources for Further Research A selection of resources for those interested in delving deeper and exploring further. Featured - A Shi'ite Encyclopedia - Abdullah Yusuf Ali's Qur'an commentary, the deletion of the merits of Imams Hasan and Husayn [a], and other changes - Al-Muraja'at (The Right Path) - Event of Ghadir Khumm - Imamate and Leadership - Nahj al-Balagha (Sermons, Letters, Sayings of Imam Ali) - Origins and Early Development of Shi'a Islam - Shiism: Imamate and Wilayat - Sunni-Shia Unity - Why Follow the Family of the Prophet (s)?

extracted from al-islam.org