A broad question. I assume you've already looked into Michael Porter's 5 forces model. If not, definitely give it a Google.

Porter's approach is supplemented (if not contested) by the Resource-Based View (RBV). According to Porter: Have a look at the sector in which you're operating and then look for competitive advantage. However, if companies of the same type as yours do the same thing, your strategy loses uniqueness, Therefore, you also have to pay attention to your own resources as a basis to built competitive advantage.

And when you review your own resources, the strategic thinkers within the firm would focus on the firm's unique strategic assets for competitiveness: unique resources,  products & services, unique competencies, network & alliances, brand value, and orientation of the firm to find and exploit opportunities. 

The parameter of  business competitive is having a different  new thing compare others as it mention on the five's Porters

Concerning business competitiveness and strategic thinking, I can recommend the work of Kim and Maugorgne on “Blue Ocean Strategy”. Based on a study of 100 leading companies in different industries, they argue that companies can succeed not by battling competitors in a bloody “red ocean” but rather by creating ″blue oceans″ of uncontested market space (with the help of a strategy canvas and a so-called value innovation). They assert that these strategic moves create a leap in value for the company, its buyers, and its employees, thus unlocking new demand which, in turn, makes the competition irrelevant.

It is indeed a broad question and there are many models to consider for different organizations and industries. I wrote co-authored an article a few years ago titled "Expanding the Model of Competitive Business Strategy for Knowledge-Based Organizations" for the International Journal of Knowledge-Based Organizations, 2011. Here is the abstract:

"The established competitive generic business strategy model continues to be the dominant paradigm, despite the rapidly changing internal and external environments that companies face today. This article evaluates other strategy-related elements identified in current business research and determines if an expanded model can be applied to companies that have become more knowledge-based organizations. Ten such companies are selected for case study examination of their generic strategy, purity of usage, innovation, strategic entrepreneurship and clarity. The results provide a potential basis for an expanded model of the dominant competitive business strategy paradigm that includes these additional elements and provides a framework for future research."

Article Expanding the Model of Competitive Business Strategy for Kno...

I think knowledge is the most important competitive-driver fact. You can look knowledge-based theory of the firm.

Hi Ann,

The question is beyond a scope, each industry should have its own differentiation between competition. For example, a luxury goods industry cannot have a price advantage with lower price (due to the kind of industry it is, it caters to a niche). Likewise, for consumer goods, price holds an advantage, but so does relevance and the quality of output. In ICT, relevance is the most important factor due to lower SDLCs these days. I was always attracted to True Blue Ocean strategies, but they are fantasies. 

Certain authors argue for general adaptability (https://hbr.org/2011/07/adaptability-the-new-competitive-advantage), some argue for strategy (https://hbr.org/2004/07/value-innovation-the-strategic-logic-of-high-growth) while most argue for Cost/Differentiation/Innovation/Operation Effectiveness Strategy(Michael Porter, everything he has ever written demonstrates this).

But I think Cost/Differentiation/Innovation/Effectiveness in delivery still does not truly reflect overall competitiveness as it is industrially driven. So, you would be best served by approach this question form an industrial context for a clearer answer.