First time ever to travel on Amtrak! Any hints, tips, or suggestions?

If you get a sleeper car, your meals are included. If not, bring a comfy pillow if it is a long trip. Also the food on the train is pretty good, but you can bring your own if you wish, like sandwiches and snacks. train travel is very relaxing and you really see so much from the train. Enjoy.

Bring lots of patience.
AmTrak does not own their rails. Thus they are subjected to delays. Not unusual to be sitting in the same location for a few hours. So just consider their “schedules” as mere guidlines. And prepare mentally. Not being negative-just factual.