It turned my whole year around to find my own answers to those same questions -- I've learned I'm long biased so every chart looks like its going up even the ones that are just the inverse of whatever I'm looking at lol.  I use Matt's $NAHL indicator and add that COMPQ has to close > 0 three days in a row AND SPX has to close > 200 DMA. That's my checklist. Until/unless that happens, its the "bear market playbook" for me:

1) Look primarily for mean reversion trades instead of trend following (like the  systems do)

2) Take profits aggressively instead of letting things run

3) Keep a large cash position and stay hedged/market neutral most of the time.

Also I chose 3 days in a row bc Matt has mentioned it can close > 0 1-2 days in a row during a bear market, so 3 should be more meaningful -- its also not a buy signal, just a mindset change for me, the bull market playbook is basically the opposite of the bear. 

Would be really interesting to hear what strategies are working for other others right now. 

You can start by listening to the post I made last night where some of those items are discussed  -  for example when SPX to GDP ratio isn't at 180 percent (and in the midst of a recession to boot) aasxwell as the FED in a tightening mode.  It's amazing to me that some have already forgot about those facts and that inflation is FAR from being at the 2% stated goal.  BUCKLE UP THIS FALL because it's likely to be quite dicey.

https://youtu.be/m-scbvT8Jpg