how to provide a steady voltage, in case of source voltage drop due to heavy consumers in the circuit
Connect the +ve of the power source to the anode of a diode.
Connect the cathode of the diode to the +ve of an electrolytic capacitor (100 uF and up).
Connect the -ve of the capacitor to the -ve of the power source.

Connect the VCC of your circuit to the +ve of the capacitor.
Connect the GND of your circuit to the -ve of the capacitor.

The diode will prevent the capacitor from discharging into the "heavy current consumers" when they turn on momentarily and will prevent the dip on VCC.

If the dip is too much and is critical for the functioning of the "heavy current consumers", you need a capacitor between the +ve and -ve of the power source as well.