Al Ries wrote this classic book in 1996. Highlghts from the book:

The five steps that big retail operations have taken in becoming retail 'category killers':
1. Narrow the focus
2. Stock in depth
3. Buy cheap
4. Sell cheap
5. Dominate the category

Four ways in which focus can improve the perception of quality:
1. The specialist effect ­ by positioning your company as doing nothing but making a certain product or providing a certain service, and that all your energies are focused upon doing that to the best of your company¹s ability
2. The leadership effect ­ by being the first company to offer a product or service, or by being the largest company to offer it, conveys the idea that the company is setting the standard and therefore must be the leader in product quality
3. The price effect ­ the highest-priced product in the category is generally perceived to have the highest quality (think of Rolls-Royce or Rolex)
4. The name effect ­ a powerful and evocative name for a product or service can help develop an image of high quality. "Other ways to improve the perception of quality is by changing the "look" of the product, the packaging, and the name. Perhaps the most important aspect of quality is the name itself. It's especially important to use a specialist name rather than a generalist name." "(p.93)

The fifteen keys to an effective focus:

What a focus is:
1. A focus is simple
2. A focus is memorable
3. A focus is powerful
4. A focus is revolutionary ­ What Ries has to say here is quite interesting:
5. A focus needs an enemy
6. A focus is the future
7. A focus is internal as much as external
8. A focus is what the country needs - "Countries shouldn't fight the focusing process. Let competition dictate which countries make which products and services. Let's all end trade barriers, which only protect the inefficient producer and do nothing for the customer and, in the long run, nothing for the employee either" (p.283)

What a focus is not:
9. A focus is not a product
10. A focus is not an umbrella
11. A focus does not appeal to everybody
12. A focus is not hard to find
13. A focus is not instantly successful
14. A focus is not a strategy - Ries' complaint here is that a strategy is in most cases, too broad and growth-oriented, giving the company, if anything, a motivation to become unfocused through diversification, acquisition, line extension, etc.
15. A focus is not forever: "Sooner or later, even the most powerful focus becomes obsolete. That's when a company must refocus itself."

[From the Great Books Series. Also see The Success Manual  - Encyclopedia of Advice, which contains summaries of 100+ Most useful books.]