One easiest way is to do it externally by unscrewing the intake pipe then pulling it off the throttle body with a little force to exopose the throttle plate.
Then hold a torch and see the condition of throtlle plate especially the outer periphery, if the throttle body needs service there must be sticky substance like engine oil deposits mixed with dust which tends to seal the air gaps totally thus reducing the airflow in the intake at idling.
Rotate and hold the throttle plate from the throttle cable linkage pulley and spray throttle body cleaning spray around the plate and clean it with a rag.
If you want to go a step further, then unscrew the MAP sensor and spray the cleaner liquid in the hole for the MAP sensor on the throttle body, do not spray inside the MAP sensor just clean the sensing port of the sensor externally with a cloth.
Fix the MAP sensor and start the car, during initial warm up period spray the cleaner inside the two opening ports made inside the throttle body. Upper one is for the IACV and lower one is for the mechanical FITV (Fast Idling Thermal Valve).
However, the best way is to remove the throttle body, clean it properly, check it for defects, fix it back and calibrate the TPS. Also remove the FITV and IACV and clean them thoroughly.
