1) Russia cut off France's supply of food from the land they were fighting on, as the Russian army asked the Cossack's to burn whole villages and plants so that the French army would not be able to eat and sustain itself while fighting.
2) The nearing winter left the French unprepared with only summer clothes and not many resources to be able to handle the different climate and territory of Russia.
3)Although the Russians retreated often, the Cossacks were at the frontline harassing the French and causing altercations which equally caused death.
