I am working on a task to predict the sales of all the items offered in all the countries. The sales are aggregated on a daily and country level. Each Item has a history of past sales and prices for a given country. I want to predict the sales in upcoming n days.
Items have different sized histories, with some items being on sale for months, whereas others have been on sales for just a couple of weeks. Also note that during data analysis i noticed that price influenced the sales, when it is reduced customers bought more items of that type.
I just want to know the approach in predicting the sales. How should i approach in predicting the item wise sales and the effect of reducing the price. What should be my path to follow ?