Question #2 : What is Strategy?
Question #2a : What is a tactic?
Strategy is when someone must take into account their surroundings/circumstances and formulate a plan based on that, as opposed to maybe just button-mashing your way through a bunch of enemies. :P
A tactic I would say is a pre-planned strategy than can be applied to a certain situation.
Yeah, I guess.
I think the two words operate at different levels. Tactics seems in my mind to be more on the execution-level, foot-soldiers if you will, whereas laying a strategy seems more like a general's job, the overall plan, e.g. for the war, not just a tiny battle :)
Note: English is not my mother tongue!