Competitive strategy is where the decisions of the individual or organisation are impacted by the decisions of others in a defined game or situation. Strategic management is a term which refers to the development of a strategy in a commercial context. In some literature it is used interchangeably with the concept of strategic planning, whilst some academics see as an evolutionary step from strategic planning in which the organisation creates the future, rather than reacts in response to it. On this web-site, the term corporate strategy is used refer to strategy in the organisational context and distinguish it from the generic concept. Its primary focus is developing competitive advantage.
Tactics relate to decisions made over a shorter time horizon.
To use a military analogy, successful tactics win a battle, a successful strategy wins the war. However, the boundary between tactical and strategic decision making is a subjective one.