Knowing your numbers, such as COGS (Cost of Goods Sold), as a business owner is a MUST and sometimes you have to look outward to get the detailed help you need. Clinton Brown and Lauren Forsch with Alluvio have helped me with my business, Rebekah Scott Designs, to figure out how to grow and be more profitable.
How to start a COGS sheet:
Break down the components for each item/product you offer
Have a friend (or hire a consultant) help you
Figure in direct costs (labor, materials, etc.)
Figure in indirect costs (marketing, postage, etc.)
Know your margins and figure out your industry standards