It starts with researching the market, know your competitors, demand and supply.
1) How much time, materials and expenses does it cost you to make and sell 1 unit? What is your break even point? What are your desired profits? What is the current cost of a similar product/service?
Do the math early and financial calculations in your business plan:
The formula for calculating net income is:
Revenue – Cost of Goods Sold – Expenses = Net Income.
Gross income – Expenses = Net Income.
Total Revenues – Total Expenses = Net Income.
Net Income + Interest Expense + Taxes = Operating Net Income.
Gross Profit – Operating Expenses – Depreciation – Amortization = Operating Income.