Often I see people flying long haul with maybe 3/4 waypoints in their flight plan. I think everyone would benefit if we used the brilliant website www.FPLtoIF.com - it is linked to sim brief and flight aware and creates realistic flight plans that can seamlessly be transferred into Infinite Flight, creating realistic flight plans for us simmers to follow. I have set our steps for you all to follow as some people might find it difficult to initially set up a flight plan correctly.
NOTE: you must created your FREE Simbrief account before proceeding with the steps below
Step 1: open to FPLtoIF website and click Simbrief -> Infinite flight
Step 2: Insert all relevant flight details to allow for a more accurate flight plan
Step 3: Copy the created flight plan and remember the highlighted flight details (fuel, alt, passengers, cargo etc)
Step 3: Spawn in your selected aircraft at your departure gate (try select a relevant gate). Also click on the top right where you search for waypoints/airports
Step 4: Paste the flightplan that you copied from FPLtoIF.com
Step 5: Your flight plan is now complete and now you can embark on your flight, be it 15 hours or 1 hour. Enjoy!
Apologies if the amount of pictures is against the rules, I just found it would be far easier to explain via the pictures.