First whiteboard interview Tuesday. Any tips?

Don't get lost in the details. Try practice writing pseudo code, look at it, and see if you could've re-written it perhaps a bit more concise.

(And if you don't know what pseudo code is, you need to look that up right now.)

1. Tie your shoes
2. Run fast

I did one years ago,questions had nothing to do with code but were problem solving questions, they wanted to see how you approach the problem. Didn't write a single line of pseudo code but spend 2hrs writing and explaining answers and reasons for the approach.

got the job but it was the worst job I've ever had, I quit 6 months in and never looked back

Don't overthink. Start with the easy solutions to show you understand the question and the concept they are testing, then work from there to improve your answers. Explain your steps and thinking.

Don't use permanent marker.

Find a friend to do some whiteboarding with beforehand, just doing the motion, getting up on the board and thinking out load in front of someone is valuable if you haven't done it before.