Do I need a Japan Rail Pass?

Not for navigating within Tokyo. The JR Pass is for long-distance shinkansen travel. For local Tokyo transit, it is a waste of money.

Can I eat on the train?

No. Eating and drinking on local commuter trains is considered poor etiquette. Save the snacks for when you arrive at your destination.

What happens if I don't have enough money on my IC card?

Don't panic. There are 'Fare Adjustment' machines located right before you exit the ticket gates. Insert your card, pay the difference, and the machine will update your balance.

How to navigate Tokyo's train system like a local

Get a Suica or Pasmo card on your phone, use the Japan Transit by Jorudan app to find your platform and exit, and always follow the floor markings to line up for the correct train car. Avoid the rush hours between 7:30–9:30 AM and 5:00–7:30 PM to keep your sanity.

Set up your IC card immediately. Open your iPhone's Apple Wallet, tap the plus sign, select 'Transit Card,' and add a Suica or Pasmo. You can load it with yen using a credit card instantly. If you use Android, use the mobile Suica app or a physical card if your phone doesn't support Osaifu-Keitai.
Master the 'Transfer' game. Download 'Japan Transit by Jorudan.' Enter your start and end station. Look specifically at the 'Boarding Position' info it provides—it will tell you exactly which train car number is closest to the stairs or escalator at your arrival station.
Follow the floor arrows. Do not stand in a clump. Look at the platform floor for stickers. Line up exactly where the arrows point; Japanese commuters are disciplined, and cutting the line is considered rude.
Navigate the station exits. Tokyo stations are massive complexes. Before you leave the ticket gate, look for the yellow or illuminated signs listing nearby landmarks or street numbers (e.g., 'Exit A4'). Choose the wrong exit and you could be a 15-minute walk from where you need to be.

Do I need a Japan Rail Pass?: Not for navigating within Tokyo. The JR Pass is for long-distance shinkansen travel. For local Tokyo transit, it is a waste of money.
Can I eat on the train?: No. Eating and drinking on local commuter trains is considered poor etiquette. Save the snacks for when you arrive at your destination.
What happens if I don't have enough money on my IC card?: Don't panic. There are 'Fare Adjustment' machines located right before you exit the ticket gates. Insert your card, pay the difference, and the machine will update your balance.