1)Dont add too much water in the sooji, it may need just few spoon.
2)Dont add too much flour, it will make the poori soggy.
3)Knead the dough really well.
4)Frying the poori in medium hot oil for a longer time makes it crispy. If you fry on hot oil, it will turn golden soon but as it cools it will get soggy.
5)You can store this in a air tight container for upto 1 week.
6)When you are making the puri, always keep the dough covered or it will dry up.