Imam Abu Hanifas full name was Numan bin Thabit bin Numan bin Marzuban. He was born in Kufa in the year 80 and passed away in 150 after hijrah. After studying the basics of Deen, Imam Saheb engaged himself in trade. Later on through the guidance and encouragement of Imam Shabi (Rahimahullah) he left his occupation and dedicated all his time towards gaining the knowledge of Deen from the Tabieen.
Imam Abu Hanifa dedicated his time to seek the knowledge of Deen under the tutelage of approximately four thousand great scholars the likes of Ata bin Abi Rabah, Alqamah bin Marthid, Imam Baqir, Salama bin Kuhail, Ibrahim al Nakhai, Imam Shabi and Imam Zuhri. They were regarded as the giants of knowledge and authorities in Deen.
Imam Suyuti (911) (Rahimahullah) mentions that Imam Tabari (478) (Rahimahullah) has a write up on a few ahadith from Imam Abu Hanifa (Rahimahullah) which proves that he actually met the following Sahaba: Anus bin Malik, Jabir bin Abdullah, Abdullah bin Jaza al Zubaydi, Maqal bin Yasaar, Wathila bin al Asqa and Aisha bint Ujrah (Radiallahu Taala Anhum Ajmaeen)
It is mentioned in the hadith:
عن أبي هريرة، قال: قال رسول الله صلى الله عليه وسلم: لو كان الدين عند الثريا، لذهب به رجل من فارس – أو قال – من أبناء فارس حتى يتناوله()
Abu Hurairah (Radiyallahu Anhu) narrates that Rasulullah Salallahu Alayhi Wasallam said: If Deen was suspended from Pleiades and the Arabs are unable to reach it, then a man from the sons of Persia will be able to reach it. (Muslim-2546 Darul Fawaid) 
Alama Suyuty (Rahimahullah) mentions that this hadith refers to Imaam Abu Hanifa (Rahimahullah). The reason being that there was no one equivalent to that level of knowledge during his time. 
Not only was Imam Abu Hanifa (Rahimahullah) an Imam in fiqh, but he was extremely pious and was a man of taqwa. Consider the following praises about him from his contemporary’s: 
Yazid ibn Harun (Rahimahullah) (118 – 206) said: I have not seen anyone more intelligent, nor more virtuous, nor more reliable than Abu Hanifah (Rahimahullah).
Yahya ibn Ma‘in (Rahimahullah) (233) said: I heard Yahya al-Qattan (196) say: We have sat in the company of Abu Hanifah (Rahimahullah), by Allah, and we heard from him. By Allah, when I would look at him, I recognised in his face that he feared Allah! (Tarikh Baghdad 15:482)
Yahya ibn Ayyub al-Zahid (Rahimahullah) (168) said: Abu Hanifah (Rahimahullah) would not sleep at night i.e. he would stay awake in worship. (Tarikh Baghdad 15:483)
Ibn ‘Uyaynah (Rahimahullah) (197) say: My eyes have not seen the like of Abu Hanifah (Rahimahullah). (Tarikh Baghdad 15:460)
Ibn al-Mubarak (Rahimahullah) (181) said:
“As for the best faqih of people, he is Abu Hanifah.”
“I have not seen the like of him in fiqh.”
“If anyone has the right to issue verdict (Ijtihad) using his opinion, then, Abu Hanifah (Rahimahullah) has the right to issue a legal verdict using his opinion.”
“When [the opinions] of these two, meaning al-Thawri and Abu Hanifah (Rahimahumullah), converge on something, that is strong.” (Tarikh Baghdad 15:470)
2) We follow the fiqh of Imam Abu Hanifa (Rahimahullah) to be able to correctly follow Shariah, the Quraan and the Sunnah. 
3) You may go to the following links for more details on Imam Abu Hanifa:
And Allah Ta’āla Knows Best
Checked and Approved by,
Mufti Ebrahim Desai.
مكانة الاملم ابي حنيفة بين المحدثين جامعة دراسة الاسلاميةتاريخ بغداد دار الغرب الاسلامى بيروت  تعريف المذهب الحنفى: هو عبارة عن اراء الامام ابي حنيفة و اصحابه المجتهدين في المسائل الاجتهادية االفرعية و تخريجات كبار العلماء من اتباعهم بناء على قواعدهم و اصواهم او قياسا على مسائلهم و فروعهم (المذهب الحنفى ص29 مكتبة الرشد)