The way you are doing it is the most common. Not a great answer, I know.
This type of movement is much easier to achieve in programs with a motion curve editor – which AE lacks, incredibly, to this day. The type of function curve required to make this movement is called Hemite, which allows one side of the bezier handle to be adjusted independantly of the other (like in Illustrator, and many other Adobe products). There may be other names for it, but the concept is the same.
You can write support@aftereffects.com and request this feature, or request a revamp of the motion curves controls. The more people that do, the sooner we’ll be out of the dark ages…. seriously.
K