It depends who you are and what you know really. I mean in the 08 crash ideally you'd be "John Paulson made over $15 Billion for his firm by betting against sub-prime mortgages" but it's hard to pull that off. For the average person probably life as usual but don't leverage up too much. For someone a bit more active it might make sense to sell property if you think you are at the top of a bubble and maybe rent a while. Stocks like BRKA and FFH tend to do alright both in the crashes and otherwise - run by Buffett and a Buffett copier.

Usually you will hear news of a bailout and the president will come out and tell people everything is okay so buy buy buy!

That's what Bush said a few weeks after the 9/11. That's what Obama said on the first friday of March 2009. Before the president speaks, the FED chair will give hints as well. I'm too young to remember what happened during the savings and loan crisis of the early 90s but I'm told something similar happened.

Just buy and hold and hold and hold. Crashes tend to be short lived. Recoveries take years and years.

Of course if you are greedy/ambitious, you could try to make money on the way down as well by shorting the market. But that's for the degenerate gamblers. Don't do it as it's nigh impossible to predict when the markets will crash and you may go broke betting against the market.

It's incredibly hard to time the market.

Good luck with that plan