What should I know about doing a Hanoi visa run for a tourist visa?

Yep, a few weeks ago - assuming this is for a tourist visa, it's no appointment necessary but they do close on national holidays. The website's list of requirements is correct for the most part; however, I had the required 20k baht but because my hotel reservation (which they ask for proof of) was payment on arrival, they factored that in and told me I needed a bit extra in the account, I think it was around $600USD in the end. It was processed in 2 working days for me but can take longer. My advice is give yourself a little longer than you think you might need in Hanoi to get it sorted to be on the safe side.

Check the website. It will have the requirements and also mention if they require an appointment or not.

What's a "Hanoi Visa Run"? What visa do you want?