It’s a skill you develop with time… I guess, cause I haven’t developed it yet.
Things that usually help me with this: Straighten the wires while putting them in order
If cables are too stiff, you can always either cut their tips or use a plier
Pressing with a finger can help you hold the wires in order
While ordering them, you can try the wires on the rj45. It has little guides that help you straighten the wires.
No love for cmus and links2?