What's the difference? Strategic thinking is how you develop your game. Tactical thinking is how you use what you have to win. For example, if you have a good loop, a strategic thinker would think about what types of serves will set up your loop, and develop those serves in practice sessions. A tactical thinker would think about what serves will set up your loop in a match against a given opponent. Strategic thinking takes place during the developmental stage of your game--which never ends as long as you are still practicing. Tactical thinking takes place while preparing for and playing a specific match. You need both.
Suppose you have a weak forehand attack against backspin. When an opponent pushes heavy to your forehand, you have to tactically choose whether to use your weak forehand attack (perhaps using good ball placement to make up for the weakness of the attack), or whether to just push it back. Tactically, these are probably your only options. Strategically, you should note this weakness in your game, and go practice it so next time you aren't so limited tactically.
Are you developing your game strategically, i.e. giving yourself the weapons you need tactically? Are you developing your game tactically, i.e. learning to use the weapons you have developed strategically?