One thing that always works - make sure your domestic travel is on the early-morning flights as much as possible. Those are almost always on time, barring weather delays.

Winter weather delays are typically related to fog, and quite common in North Indian airports.

With afternoon and evening flights, you will be invariably delayed. I was in India for 3 weeks in Oct and did around 10 domestic flights. First hand experience with this.

Air Deccan is definitely good, reliable and cheap, as far as airlines go. They have BoB meals, and their offerings are limited and unappetizing. Make sure you plan for that.

No experience with Go air, but they would probably be the same.