Hello!

I'm about to make my first sales forecast ever (which I believe will influence my entire online retailing model? https://docs.google.com/spreadsheet/...3RldnlsNmRvNmc), but where do I begin? Basically I have:

1. One year of sales data from my biggest competitor (what items were sold, from which country the buyers came from, and the dates of the purchases)

1.1. I do not have the prices of the items sold - but I might be able to get them. Should I?

2. Three years of market growth data (how many potential customers, and how much this number has grown to present date)

3. The various economic indicators in my Peer Company Comparison https://docs.google.com/spreadsheet/...FdNVl9jLXRpNFE

I have no idea where to start though. How to unite all of these "factors" into a clean, accurate formula or algorithm or whatever?

Thanks in advance!

Mikkel

P.S. My spreadsheets are originally Excel. In Google Docs, click File > Download as > Excel.