Here’s the latest from Venture Beat’s Entrepreneur Corner.

Ask the attorney: How founder-friendly is FF stock? – As if Class F stock wasn’t confusing enough, now there’s Series FF stock. Attorney Scott Edward Walker runs down the particulars of these founders shares – which can let some entrepreneurs partially cash out of a venture-backed company even without a sale or IPO.

Startup lessons learned from Warren Buffett – Warren Buffett’s not only the world’s richest man, he’s also a master communicator. And while you might not think there are lessons for entrepreneurs in his annual note to shareholders, Lou Hoffman, CEO of the Hoffman Agency, shows three lessons you can’t afford to miss.

Business plan not working? Time to pivot – Business plans rarely work perfectly out of the gate. When things start to go wrong, many companies begin finger-pointing and firing, but serial entrepreneur Steve Blank says the smart startup owner makes changes to the business plan.

At least one angel is looking to invest: Me – Dave Kellogg has had some hits and misses in the world of angel investing – and he’s taken the bulk of the last decade off. Now the CEO of MarkLogic ruminates on the angel world, as he starts to dip his toes back in the water.

The biggest mistake startups make – Unless you have an incredibly simple, incredibly disruptive product, you’re probably going to need bigger businesses as clients. Liz Tinkham, a global manager at Accenture, gives her thoughts on the single biggest mistake most startups make as they approach clients.