Tactic is another word for a maneuver or method. If begging doesn't convince your parents to raise your allowance, you might want to try a different tactic—like doing all your chores without being asked.
English-speakers have been talking about tactics since at least 1640, when this word was first recorded. A tactic is just a way to do something, a plan, or an approach. Generals have to have a good grasp on military tactics to win a battle; football teams have to use strong defensive tactics to keep the other guys from scoring. One time-tested tactic for winning over a teacher? Always turn your homework in on time!