There are great accounting software packages out there to help with this. Know what your customers are willing to pay and the value they place on your product or service. If your business is so busy that you cannot schedule any more work hours, it's time to raise your prices. Decide on an annual income goal, but do not forget to factor in your taxes, overhead costs and your profit margin. See if your industry has pricing guidelines.
Some trade associations publish and sell rate guides.
Customers may be willing to pay more for personal attention, better quality or for your special niche. Be flexible in pricing, because just as you test market your product or service, you'll have to experiment with pricing as your business grows or your market changes. Offer different prices and packages for your customers to choose from. Also, remember that the way you present your prices can influence sales. Pricing is based on an ongoing evaluation of the cost and time involved in running your business and meeting your customers' expectations.