Question

how did Surat gained its importance a a temple town?

Answer 1

Till the 15th century, Cambay was a major port of Gujarat. However, Cambay's harbour started silting up by the end of 15th Century CE and Surat grew in importance fro trade.

Answer 2

here is your answer

the modern port city of today boasts of a great historical and cultural heritage. The history of Surattakes us back to the epic age of Mahabharata and Ramayana. According to mythological beliefs, Lord Krishna stopped in the city while his journey from Mathura to Dwarka.
Surat of today has earned the reputation of an important industrial hub and commercial center of the country. A glimpse on the history of Surat will prove that the city has always been a great trading center. 

The great explorer Hiuen Tsang referred the Surat City as Sowrata and described it as a business town on the shore of Arabian Sea near Gujarat. The Brahmin Pundits of the thirteenth century called the city as 'Suryapur'.
Surat reached the highest point of prosperity during the sixteenth century. The Surat Port was considered important by the European traders. The British and the Portuguese waged battles against each other to gain supreme control over the trading route. The French and the Dutch also arrived in the city with merchandising objectives. 

The great Maratha warrior Shivaji attacked the city several times to usurp its wealth. In the beginning of the nineteenth century, the British gained overall control over the city. Since then, the city witnessed plenty of movements and agitations against the English atrocities. It has contributed a lot to the freedom movement of the country. Surat reorganized itself after the independence and soon emerged as one of the significant cities in India.