What is the basic rule to calculate values of the coupling and bypass capacitors in a transistor amplifier?

Question

What is the basic rule to calculate values of the coupling and bypass capacitors in a transistor amplifier?

Answer 1

The reactance of the capacitor must be less than (perhaps by a factor of 10) the equivalent series resistance of the circuit, at the lowest frequency the circuit is designed to pass.

"equivalent series resistance" depends on the circuit. For a bypass cap, it's the resistance it is bypassing. For a coupling cap, it's the sum of the collector resistor of the preceeding stage and the base resistance of the next stage.

Xc = 1/(2πfC)