Thanks guys. I have tried adding more segments before. Actually, I'm modeling a complex object like this (1st image) which has a cylindrical part which attached to some other parts. So it is very hard to add more segments. Applying subdivision level 1 to that cylindrical part (2nd image hard edges defined) and adding edge…
What Brygelsmack said. Basically, the more complex a shape on a curved surface needs to be, the more divisions you should start with before adding those complexities. (In the image below you don't necessarily need all the circumference loops on the right example but you definitely need to begin with more sides to your…