First and best tip is to always book in advance, when you are in hurry you will end up paying more.
Have you noticed that ticket prices increase when you repeatedly check them? this happens because Google tracks your cookies, try using incognito mode while checking for prices.
Compare prices from both travel booking sites and airlines, look for sign up offers.
Use cashback and coupon websites like PaisaWapas to get extra discounts on ticket bookings.
Try to avoid weekends adjust your plans to weekdays so you can save on the price drops.
Since Tuesday & Wednesday are most working days of the week you will get cheapest deals on these days.