This is the formula I use for forecasting in Capsim:

1) total industry demand*industry growth rate*last year's market share

2) Then I forecast my production by multiplying the forecasting formula * (20% + last year's market share)

3) Once I have this results I just subtract my inventory on hand from results in 2)

I keep running out of inventory in half my products and have so much leftover from another product.

Is there any forecasting and production formulas that I could use to more accurately predict?