Booking a flight from Delhi to Bangalore involves choosing an airline/platform (like IRCTC Air, IndiGo, Goibibo, Skyscanner), entering travel dates/passengers for options, selecting a flight, providing passenger details (name, contact, DOB), paying, and receiving an e-ticket with details like PNR, flight number, and timings for your journey. Prices vary, but booking ahead often yields lower fares, with January sometimes being cheapest.