What are the mechanics of modern-day budget traveling? Everything starts with a rough plan: when will you leave, and when will you return. I have traveled before with only the date of departure fixed, but lately my travels have been hemmed in by two dates. [I like it when only the date of commencement of a tour is fixed, the other date is unknown. That kind of travel is very much like your life: you only know the date of your birth. Yes, you will die one day, but you don’t know the date, and you don’t care either. Life is too short to waste worrying about the death.] Once the dates are fixed you do a rough allocation of your time in the places you will visit and see if there are is any air ticket involved. If there are air tickets involved you do a quick Internet search to get a feel of the costs: you find the fare for today (whatever date you are checking the fares on), for next day, for a week later, for a month later, and for three months later—you also check the price difference between flying on weekdays and weekends. Once you have bought your airline tickets you work on other details, but many of these details are worked out once you have your boots on the ground. You always keep an eye on things e.g., train/ferry tickets, hotels at hot tourist attractions, etc. that will save you money when you book in advance.
In our Australia-New-Zealand-Fiji travels, our main ticket was with Fiji Airways, with a separate Sydney to Auckland ticket from LAN.