I am trying to predict sales quantity based on attributes of the item.Sales are aggregated by week wise and prediction is also done by week wise.I am having large number records with zero sales quantity than compared to positive sales(for 20 positive sales 250 zero sales records are there).I want to increase my training data by adding small values to sales quantity and combining with total records. At present I am using RANDOM FOREST and NEURAL NETWORK .I am not getting any good results Please correct me if anything is not considerable.
Can anybody suggest way to increase my training data