Branch transfer at any campus of BITS is not easy. You should be amongst
the top 5-10 students of the entire batch to have a realistic chance of a transfer. So any senior would suggest you not to take a branch thinking of a branch transfer the next year.
For your next question, branch transfer requires a lot of determination. You should remain focused all throughout the year, attend all the classes(at least the tuts),work dilligently, score well in every test/quiz and also pray that others (barring countably few) do not do better than you in them