The most successful businesses in the world -- and usually some of the best investments -- have brands that are easy to define and possess just a handful of key qualities.

Just think of how many successful companies can be summed up in a few words.

Wal-Mart (NYSE: WMT) is known for 'low prices.' Apple (Nasdaq: AAPL) is 'innovative and cool.' Berkshire Hathaway (NYSE: BRK-B) is 'trusted.'

All of these firms have also carved dominant niches that make it clear to investors exactly what they can expect from these businesses, and why they should be excited about them as investments.

Firms that don't follow this mantra struggle.

Here are the list of seven key qualities I look for in a great business. When I find businesses that meet all of these criteria, I simply buy them and hold them indefinitely.

The world's greatest businesses sell their products at premium prices.

Consumers need a justification for paying premium prices. An iPhone is more exciting than an LG Optimus. Coke (NYSE: KO) is more loved than Mr. PiBB. There's something more special about a diamond in a Tiffany (NYSE: TIF) box than a diamond from a local jeweler.

The world's greatest businesses sell products used in day-to-day life.

The more complex product becomes, the tougher your business execution gets. The world's best businesses are companies that sell products that consumers need and use regularly in their everyday lives.

The world's greatest businesses have a global reach and appeal for their product.

To be truly global, a business must offer a completely new experience, unavailable in the homeland -- the way a firm like Starbucks (Nasdaq: SBUX) does.

The world's greatest businesses have unlimited growth potential.

The world's greatest businesses have clear competitive advantages that dominate their competition.

The world's greatest businesses generate enormous cash flow with low capital spending requirements.

The world's greatest businesses have extremely high profit margins.

The world's best investments hold these simple yet fundamental things in common.

When you find a company that meets all of these 7 traits, it could turn out to be an investment that will generate value for years to come.