Be explicit about your assumptions, so you can test them...

Business Model Assumption

If you develop something truly new to market, the business case will be based on a lot of assumptions and guesswork. But if you know what your assumptions are, you can test and qualify them. 

It is especially valuable if you can quantify your assumptions.

Revenue

We believe that customers are willing to pay for...

We believe that the lifetime value of a customer is will be....

We believe that the annual value of a customer will be...

Price

We believe that a price most customers in our target segment are willing to pay will be....

Costs

Channels

Customer Relation (Get-Keep-Grow)