When will be a good time to buy airline tickets to Hawaii?

i am a novice at buying airline tickets and is planning to take a trip to Hawaii in December and are currently looking for tickets and they are extremely high! 900+ and i refuse to pay that much when i hear people are buying them for 320-340! so when will be a good time for me to really start looking into buying the tickets and where should i look? I'm a student so does that play into any discounts? Thanks in advance