Let's see from the perspective of his relationship with Punz. I think he bonded with Punit, initially because Punit seemed to have some kind of influence in BB and outside. Punit is a well known director and has a huge network in Bollywood, but also inside BB, he was one of the strongest personalities who intimidated everyone and BB seemed to have a soft spot for him. Gautam was smart enough to bind himself with a man who could take on anyone inside the house. Yes, I do think that their relationship from Gautam's end became very genuine later and he was vey attached to Punit, but that association hs definitely helped his game, because that made P3G, that made Gautam look very sentimental towards someone, showed his fierce loyalty towards a person he loves and he got unconditional support in the house where everyone initially hated him.
Now, playing the victim card, is his game. In the first week, he did nothing wrong and yet the whole house acted like a stupid herd following each other and isolated him. He was genuinely affected by it, but did not realize that outside, the public has come out in such a strong support for him, because of this being a lone warrior kind of image that has come out. He is the only contestant who has taken full advantage of the feedback by every panelist and Salman Khan. He very keenly changes his behavior whenever there is any negative feedback on him or maintains the stance when it's positive feedback. All other housemates have been so ridiculously stupid to not play the game keeping in mind every week's feedback. He understood public likes him when he is alone and isolated and hence the " main akela hoon" self-talking all the time. It's a brilliant game and he plays it better than anyone else. Ali has tried it, Upen has tried it and they have failed miserably. Gautam not only plays it like a boss, but also comes across like a genuine bichara.
Coming to challengers, he knows that they have the upper hand for the first 2 weeks as BB will give them a lot of leverage in tasks, in nomination or whatever. Any way, the champions are not his friends, except Pritam and even Pritam is an oscillating machine, depending on where his palra is bhaari, and he does tend to go towards Karishma when she is alone. :P So, Gautam won over the challengers, by being closer to them. This way, they will never nominate him, plus champions even if they do, he knows he wins the polls against them. Plus, them being against him, becomes another victim card for him to play in. Also, Mahek came in as his challenger, and his biggest move was to befriend her as she is the strongest contender from challengers.
If you go to see in that sense, Gautam has been the biggest, smartest and coolest player so far in the BB house and he plays so dumb about his game that everyone thinks he is dumb and has won only on being dramatic or victim card or on his body and looks. Truth is, he has come so far, because he is the only one who has learnt to take that feedback and give out an image to the audience that they will love and support and he has been the most intelligent in the lot about it. I give him full credit for his game and for being so popular outside. It's not his body or looks, but his smartness and intrinsic ability of understanding the game and playing it that has won over. Gautam FTW for this reason alone!