The data sheet usually states the capacitor size range for input and output. Example: 'Cout needs to be larger than 0.1uF'
The inductor is not needed but helps with high frequencies. The ripple rejection is graphed from 100hz to 10khz. At about 5khz and above the rejection gets increasingly worse. The output LC resonant frequency could be set to 10khz to 100khz to help with HF noise. Some companies show a graph of the response of the regulator with different amount of capacitors.
Cin is mostly a function of where you are getting the power from. (50/60hz ripple needs larger capacitors)