1. TT to January 1st.
2. Go to the ATM and get your 500 free nook miles. Because it was closed yesterday, you automatically get the 7+ day bonus for tomorrow (January 2nd).
3. Do any easy nook miles tasks that you have, such as: take a screenshot, talk to your villagers, change your clothes, hit a rock, chop wood, sell fruit, sell 5k worth of items, buy 5k worth of items.
4. Once done with the tasks, proceed to January 2nd.
5. Visit the ATM to get your 300 nook miles bonus.
6. Repeat step 3: do easy nook miles tasks.
7. Once done with the easy tasks, TT back to January 1st. You're now at step 1, and you repeat all previous steps.