How to quickly lose body fat?

I am a year-round volleyball player and my school season has just started. Every year during club season I put on some extra body fat due to less practice and workout sessions. We have a new trainer this year and he does not work us out at all. I cannot fit comfortably into my uniform and spandex and the extra body fat makes me feel sluggish and out of shape. When I am my most fit and smallest, I weigh about 135 but I am still 147 right now. This time last year and every year before, I would be at 135ish. How can I quickly lose the body fat for my season?