I would take a small piece of what you are cooking a
nd put it carefully in the oil.
If it is ready, it should immediately start to bubble and fry.
prinkle some flour if it sizzles its hot enough
if u are doing somthin like french fries
add a fry in the middle of the pan
not the side
middle is more hot
use a set of bamboo chopsticks.
if the start bubbling at the tip the oil is ready.
Generally if you see even a little smoke the oil is getting too hot.
If it is dunp in all of the chicken in and it will cool the oil off.
I generally take my oil to 380F then put in the food.