Startup 101

I am seeking expert info from people that experienced start ups before. This is probably discussed a lot before, just trying to consolidate all info in one megathread. What to look for when joining startup, how to at least avoid getting into a guaranteed failure? How to maximize financial gain? How to handle taxes with options grants? There were some past thread where a few people (think someone from roblox and amazon) were giving great advices, but can't find them anymore. Feel free to drop the link below if you can find. In general, what are the advices, and what are the deal breakers?