Your word choice reveals your attitude and intelligence. Enlarge your vocabulary. Replace nice, great and busy with appealing, stellar and preoccupied. Find concise ways to express your emotions. Trite phrases show a lack of imagination.
Point jokes inward.
If you're going to tell a joke, make sure it's at your expense. Don't assume others will laugh at jibes directed at them or their colleagues, even if you are teasing. Keep it simple. Reduce your message to clear, direct points. Strip away needless detail or aimless tangents.