Did not pay for prep. Most of the free advice out there is just as good. Just be yourself - there really are no tricks or hacks to get the call.

I made up a mental framework on how I would handle the LOI on the day of the LOI after the briefing that tells you what to expect. Work through the problem until the clock ticks “0”. Then with the paper and pen that they give you, write an honest critique on your performance. This is more important than your actual performance.