Valuation & Appraisal
When an entrepreneur prepares to sell a business (or buy a business) they should begin to engage in an honest evaluation of the total value of the business. They can begin by looking at the parts of the business to see which parts are of value and what that value might be.
Most businesses have very tangible parts (material, facilities, etc.), nearly all have intangible parts (contracts, quality staff, certifications, etc.) that can be evaluated for their value to a buyer.
Some of these parts whether tangible or intangible have very core functions exclusive to the business' main operations (i.e. a trucking company has trucks and delivery contracts) and some that may not have as direct core functionality (things that might be absorbed in a consolidation move like internal accounting services or dispatch).
Now the entrepreneur can look at what a buyer might be interested in and see what value is in a business. There may be things that might also be of interest to a buyer. This might be how well the business operation is running and how quickly, effectively, and efficiently the business can operate after the sale.
All of this requires making the business operational beyond the built legacy of institutional knowledge. The entrepreneur should begin "working on the business" as well as "working for the business."
You may also want to secure any "handshake deals" or contracts and getting those on paper, thus making them measurable assets.
One of the items a potential buyer, you as a seller, or certified appraiser will look at is the business' books. They need to see if the business is structured in a way to make the sale a win. One of the tools the evaluator will likely use is key business ratios (or financial ratios). This will tell the evaluator if the business operates along general financially successful guidelines for other similar businesses.
There are multiple organizations that train, certified, and continually educate business analysts and appraisers. You can find them through these organizations and verify any credentials through these organizations member listings. Remember that there will likely be some form of financing involved and the financier (likely a bank) will have an appraiser or be able to suggest a few.
