I have already checked this. He used ensembling of gbm and neural network. I am new to data science, heard a lot about xgboost so just trying with it. But Not able to beat linear regression. After doing little bit feature engineering and feature selection I find out the following predictors which I am using.
Item_Sales/Item_MRP(Item_Sold) ~ Outlet_Location_Type+Outlet_Size+Outlet_Type+Year