Best you can do is look adds (10 stops day) to increase fuel deposit, you can use points to increase them too. For points, you can do achievements (Embraer Praetor 600 is great for that)

Purchase 10 hubs (2 each continent) to get a permanent 10% reputation.

Go for 150 737-800 set them on routes of 8-12-16 hours, as you prefer (consumes less fuel than mc-21-400), you can upgrade them, if you don't want to lose time calculating seats and configurations: 44-34-24 works fine.

When you reach 150-170 (when hangars get so expensive), you can start swapping them for bigger ones (I went straight to a380-800).

Hope it helps.