1. The mirchi incident: propelled him into limelight and made everyone take notice of him. If it was not Karishma who was yelled at, then the incident would not have been stretched so much.
2. CR room yes- no task: nobody could predict what karish and gauti would choose in the task or the fact it's shown on TV to the HM's could make a huge difference.
3. Captaincy election: is it a stroke of luck that everyone raised their hands for Gautam before realizing what they have done. Best of all, pritam rising his hand and then wondering why he did it.
4. Him being made sevak, made him close with p3.
5. Dimpy supporting him all the way.
Of course, I know it's not all luck. Gauti's personality and his patience made a lot of contribution too.