Social media might actually end up helping you out here. Follow/Like airline pages for updates on the best deals. Twitter is a very efficient tool in this regard actually. So apart from following travel portals like Sky Scanner and Make My Trip, also follow airline handles. You never know what you end up getting.
4. The right time to buy
Flight comparing websites will back me up on this. The cheapest days to book are Tuesdays, Wednesdays and Saturdays. Friday and Sundays are the busiest, hence the most expensive. Also, early morning flights are the cheapest. Sometimes, booking in the afternoon also helps as discounted flights hit the sites then. Some flight companies also have designated sale time. Like Air New Zealand puts seats up for sale up to 11 months in advance, and has a sale in January and September. Best time to book a Virgin Atlantic is January. Singapore Airlines, between December and February. British Airways, January and September