想念 (xiǎngniàn) is the everyday verb for missing someone or something you are separated from — it focuses on a warm, nostalgic feeling of absence. 思念 (sīniàn) is more literary and intense, often used in writing or poetry for deep, prolonged longing. 渴望 (kěwàng) means 'to thirst for' and is stronger, used for desires or goals, not people.