It's still all about having fun in your second year at Hogwarts but it is also about becoming more serious, mature and responsible, confident and creative, as a person, as you make the transition from informative and conceptual to more practical-based and conceptual lessons being taught to you at Hogwarts. I suggest learning to take initiative, and learning volunteering and socializing as part of your personal development at Hogwarts in your second year at Hogwarts, in addition to studying harder and more conceptually and with a more practical-based approach in your second year at Hogwarts as compared to your first year at Hogwarts. Also, just have a gross list of all possible career options for your future after Hogwarts in the wizarding world in your mind, so that your approach towards studying at Hogwarts is appropriately structured for your future years at Hogwarts. These will be enough for what needs to be done and what can be done in your second year at Hogwarts.