Studying the Lives of the Pious Predecessors
Leads one to the Sunnah 
Hazrat Shaikh Moulana Muhammad Zakariyya Kandhelwi (rahmatullahi ‘alaih) mentioned:
Continuously study and examine the lives of our Akaabir (pious predecessors and seniors).
After studying the lives of the Sahaabah (radhiyallahu ‘ahnum) I reached this conclusion that all the Sahaabah were superb. Though each Sahaabi possessed a unique “colour”, all were common in emulating the blessed sunnah of Rasulullah (sallallahu ‘alaihi wasallam). Similarly, I have also witnessed that our Akaabir (pious predecessors and seniors) possessed different magnificent qualities and all diligently held on to the blessed sunnah of Rasulullah (sallallahu ‘alaihi wasallam). These great luminaries can be compared to the flowers of a garden. The splendour of the garden can be gauged through the fragrance and beauty of it’s flowers. (Malfoozaate Hazrat Shaikh 1/25)
(Taken from http://alhaadi.org.za/)