Divide total sales by unique visitors and you'll establish a dollar value per unique visitor. In other words, if you bring in 100 dollars in sales per 1,000 visitors, your visitors will have a value of 10 cents each. Bring in twice as many visitors and you'll bring in twice as much money. The only ways to alter this equation are to (1.) sell a higher priced product or service to the same number of visitors, or (2.) sell a higher percentage of visitors who come to your site. The percentage of visitors sold is your conversion rate. Better websites have higher conversion rates. Good luck to you.