Peel potato and cut in medium size. Also cut onion in medium size (left 2-3 onions aside for fry sabzi) and then separate each layer of onion

Put the oil in pan for fry the potato
Fry potato until it get brown then put onion and fry it until onion fried well

Chopped onion very well or grind in mixer.
Chopped tomato and green chilli or grind in mixture

Put the pan on gas and keep flame medium.
Put the jeera inside the oil and when it's fried well then put chopped onion and fry it until its turn in brown after then put chopped tomato and green chilli and fry it again, once it will fried well then put other masalas like turmeric, red Chilli Powder, coriander powder and salt as per taste and stir well.
Now put the fried potato and onion in it and mix well.