I just graduated, just like you. In fact, there is no trick. I just want to talk about my method: try not to sit when you have the opportunity, because sitting for a long time will make your hips fat, and it may be impractical for students to attend classes every day. I have a good method: sit up straight, keep your feet horizontal, and so on for 5- 10 minutes. Lie on your back on the bench and put your legs aside for 5 minutes. Lift your left foot first, then do it like your left foot. In half an hour, you can try. Stick to it.