How can I quickly reach TOPIK 3 from TOPIK 2?

I want to take the TOPIK 2 exam as soon as possible, but I'm struggling with how to prepare given my current situation. I've been learning Korean for over 10 years, and I can manage everyday conversations, but the TOPIK 2 exam seems a bit different. I scored almost full marks on the TOPIK 1 mock exam, but TOPIK 2 appears to be at a higher level. My biggest weakness is vocabulary. I've been learning randomly, so I can only understand words at the TOPIK 1 level through context. My grammar isn't that great either. Should I focus on solidifying my vocabulary at the TOPIK 1 level? Or would it be more efficient to prepare by directly solving past TOPIK 2 exam questions? I want to know the most effective method. Please give me some advice!