1: People observing fast should not have a shave or haircut.
2: Devotees should not cut their nails too.
3: If you have lit up Akhand Jyoti, ensure the presence of a person in home 24x7
4: Avoid eating onions, garlic and non veg food during the 9 days.
5: People should not wear the dirty clothes during Navratra.
6: One should not use leather made products like belt, sleepers, shoes.
7: People on fast should not cut lemon.
8: While having fast people should avoid using grain and salt in the food
9: If Vishnu Purana is to be believed, A nap in the noon is prohibited.
10: If you are having a fruit, complete it in one sitting.
11: If you are chanting Chalisa or Saptashati, never pause it to talk with someone.
It will bring negative energy into your body.
12: Many a times people chew tobacco to battle hunger. Stop it, as addiction destroys your fast.
13: Be on a celibacy mode, avoid making physical relations, it hampers the result of fast.