Tactics are often associated with winning material through a combination or attack, so you could think of concepts such as trapping an opponents queen or blundering a knight are more tactical in nature. Other ideas, like discovered check, pins, decoys, etc are primarily tactical as well. Many lower level games are decided by tactics simply because players are more apt to fall into traps, not calculate properly, etc.

Strategic play is much more subtle, but becomes more important as you get stronger. Strategic play generally involves more long term planning with the goal of creating a lasting advantage for yourself. Some examples of strategic concepts are creating more space for yourself (and at the same time constricting your opponent), having a better pawn structure (e.g your opponents pawns are isolated and vulnerable to attack), having your minor pieces better positioned(e.g your bishops rake open diagonals while your opponent's are trapped behind pawns)