you can consider using regression models (linear regression, Tree, neural net etc.) across a set of similar products including the new product itself to pool information across multiple time series. You should also include the product attributes in the regression model to capture attribute specific demand features. Noticed that this regression model can be used to generate forecasts for products with different product attribute combinatiions. Using the Tree models will also give you the capability to generate forecasts with unseen product attribute values. Once the products become mature, you can use the time series models to generate the forecasts. Hope this helps Alex ... View more