The Knight of Cups encourages you to remember that victory is not just an exercise in strength of arms, but can be achieved through cleverness and a savvy mind. He can also be given to flights of wild fancy, so you may also interpret him as a warning to maintain your focus. New initiatives in your life are likely on their way, and you must remember to seek novel paths to accomplish goals, but also not lose sight of where you are going.
To get the full traditional meaning and interpreation of Knight Of Cups, I suggest you visit Trusted Tarot and their Knight Of Cups page.