If an individual is self-employed in a business that provides services (not products), then the gross income is put onto line 7 of Schedule C and is the gross receipts from that business. It will also include the amounts which are shown on Form 1099-MISC, known as Miscellaneous Income. If the buiness is selling merchanidies, then Form 1099-MISC is not required. The self employed owner is running a business which involes mining or manufacturing, then the gross income which is put on line 7 of Schedule C is the total sales from that business less the cost of goods sold, plus any income from investment which are incidental or outside the operations of the business. If the taxpayer is involved in more than one business, then a separate Shcedule C is filed for each business. For example Consulting and taxi driver). Other income will include things like bank interest, and reimbursements and rebates from government food programs. 

The formula is as follows 

Calculation of Gross Income 

Gross Receipts/Sales

(-) Returns/Allowanes

(-) Cost of Good Sold

= Gross Profit

(+) Other Income 

= Gross Income