Someone else said you can’t bring some meds, make sure to double check what you can and can’t import to and from. There are things you can’t bring back (e.g. agriculture like potted plants or seeds) too.

It’s pretty easy like they said, doesn’t require a lot of planning or thought. Restaurant reservations for some places can be difficult to acquire if you don’t know locals though. You’ll have to go through your hotel concierge

I personally recommend avoiding touristy things. I’ve found they’re invariably kinda mid. Depending on how much time you’ll have, and how many times you plan to go, I would suggest spending a few days to a week in single cities and not overdoing it with activities. Exhausting oneself isn’t necessary if you’re going to go back, and you don’t really experience it to the maximum if you’re on a strict itinerary with limited time