There are two major airline alliances which you can use to book round-the-world tickets – Oneworld and StarAlliance. Each of these are an alliance of airlines which collaborate together to allow you or purchase a ticket which either gives you a certain number of stops on any of their airlines or a set number of miles you can fly (and as many flights as you can manage on their airlines within these parameters). Each of their websites have itinerary planners which let you connect flights and input dates for your travels, and I have to say that this was very useful in planning our stops, and getting a feel for where we could and could not go. Of the two, I have to say that I felt StarAlliance had the better planning tool.
One crucial part of the process for planning our itinerary was the involvement of the company Trailfinders, who will take a list of required destinations from you, and run them through their software which will find possible routes for you, and they’ll suggest a ticket for you that meets your requirements. The guy I spoke to at Trailfinders was extremely helpful in planning our trip – unfortunately, their commission rates were very high and in the end it was significantly cheaper for us to book directly with the airline than with Trailfinders. However, I would still recommend phoning Trailfinders to run through your itinerary – they really helped to firm things up.
In the end, we went with Oneworld. The reason behind this was that Easter Island was one of our required destinations and that it could only be accessed using a Oneworld airline (Lan Chile). StarAlliance did have an excellent range of destinations, but did not suit our purposes as it did not include Easter Island. Thanks to Trailfinders, booking the ticket myself was much easier as I knew the linking flights which were required. I also managed to get a 10% discount on the overall tickets, as Oneworld were doing a promotion due to their 10 year anniversary. Overall, my advice would be to get input from a company such as Trailfinders, but at the same time not to be afraid of booking the ticket yourself and doing your own investigations – we saved a significant amount of money by booking directly with Oneworld.