Step 2: Buy your international flights
So, I have known since August of 2015 that I want my next multi-week trip to be to South America in November of 2016. However, I only just bought my tickets a few weeks ago (and that was only because I was anxious to get into specifics). I have read (and concur based on my own experience) that as a rule of thumb, the best time to get tickets is 4-6 months prior.
Even if you are not ready to buy, do some research and monitor prices. The only way you will recognize a good deal when you find it is if you know the trends. I bought my tickets from DC to South America for just over $800. In the last 9 months I never saw them go lower than around $695 (but not for the time of year I wanted to go). Only time will tell if I could have gotten a better deal (I will continue to monitor and will let you know).
To check for fares, I love Airfare Watchdog (but take it with a grain of salt), Whichairline.com, and google flights. For my trip, there is really no other option than LAN airlines. But after months of monitoring and research, in the end I bought my ticket through Orbitz.
If you don’t live near a hub, or prices are too expensive, experiment with other airports. A friend that is coming with me can’t find a ticket for under $1800 from Dallas. But if she can get to Miami for $300-$400 she can save $600 per person. That is probably worth the extra hassle/time.
For my situation, a round trip ticket with LAN airlines made the most sense. But in other situations, think creatively. Are two one way tickets cheaper? Do you need or want to fly into and out of the same location? Is there an airport nearby that has a cheaper flight? Check the website of your destination’s airport to see what airlines fly there to see if there is someone you have never heard of that might have a deal.