Doha → Delhi

Think in terms of periods rather than single days. Holiday and festival windows and school breaks are when the largest number of people on this corridor want to travel, and the lower fare levels tend to be gone well before those dates arrive. If your trip is tied to one of them, plan early and accept a reasonable fare rather than waiting for a drop that peak demand makes unlikely.

For everything outside those windows, the advice reverses: search wide before you commit. Price several consecutive departure days on this page, then do the same for your return, because the two directions do not always tighten at the same time. If you are booking for more than one person, add extra lead time — a single cheap seat is much easier to find than three or four at the same fare.

Three habits do most of the work on a route like this. The first is comparing all the airlines at once instead of trusting one carrier's page, since the spread between options on the same day can be wide. The second is comparing on total cost, not the advertised fare — baggage allowance in particular deserves a close look if you travel with more than a cabin bag, because paying separately for bags can erase what looked like a saving.

The third is simply not booking on your first search when you have time to spare. Following the route for a few days shows you how far prices move and gives you a sense of what a good fare looks like on your dates. Pingsme is free to use, refreshes at least daily and keeps everything on a single page, so a last look before you pay is quick and often useful.