Something I haven't seen yet (and something I will add, since I'm flying feeder freight) is to be sure you like flying on the back side of the clock.
- As part of your training, get lots of night time experience, including with an instructor, as necessary. Same with instrument training -- try to get night IFR experience, if able.
- Be ready to fly in all types of weather: snow storms, thunderstorms, high winds, turbulence, etc. I got my experience in a Caravan flying freight out of rural Iowa.
- I got my degree in something I liked (teaching), in case of concerns later, and took a freight job. If you're not naturally gifted at networking (I'm not), you might have to work up from a C208 or a C402, to AMF or some other larger operator, to FDX/UPS. Lots of hours, lots of long nights.