Hi, I need to travel from Shanghai to Taicang. Which is the best bus route ?

Both South Bus Station and General Bus Station provide bus routes to Taicang. You can choose the one near to your starting place.
The bus schedules of South Bus Station are from 06:45 to 18:53 at intervals of around 40 mins. The ticket fare is CNY 24 per person.
For General Bus Station, the buses are available from 07:00 to 18:55 with the frequency of around an hour. It also costs CNY 24 per person.
By the way, the trip takes around an hour.