琢磨 (zuó mo) means 'to ponder, mull over, think through' — it's a colloquial, everyday verb for turning something over in your mind, often about a practical problem or plan. 思考 (sī kǎo) and 思索 (sī suǒ) are more formal and abstract, closer to 'reflect' or 'think deeply'; 推敲 (tuī qiāo) is specifically about carefully weighing words or details.