I just came across this thread and I am interested to see what observations/advice people are offering, so thanks for posting.
I'm no expert, but I've been trading stocks for ~25 years. My wisdom is limited but simple (based on my own experiences). I got burned during the .com crash but I recognized that the downturn was also a good time to invest in blue chips because it was a no-brainer that they would recover most of their losses eventually (which they did). Unfortunately I didn't have any money to invest at the time because I had lost so much in the .com burn.
In 2007/8 I was hearing a lot about how the US housing market was in trouble and that it should impact the overall investment market. I had money to invest at that time but was uncertain where to put it so I just had it sitting in a 7% term deposit until I could figure out what to do with it. I was as surprised as anybody when the market quickly melted down in 2008, but I didn't get burned because I wasn't in it at the time. I was no investment genius... it was simply because I wasn't in play at the time.
Luckily I could take what I had observed from the .com crash and apply it. I looked for some blue chip opportunities and invested in companies I was familiar with based on my expectation that they would recover from the crash rather than failing. Emerson Electric, and Johnston Controls were my primary investments and I made 20-30% return in just a few months in 2009. Unfortunately those "wins" made me a bit overconfident in my ability to find winners so I also started playing in alternative energy stocks (mostly solar). I won't mention any specific names because I don't want to steer anybody into risky stocks. That market turned out to be a lot more volatile than I was expecting so I made a lot of big losses in addition to a lot of big wins. I did come out ahead overall, but some of my lessons were a bit embarrassing in hindsight. I did get a bit lucky in that one of my solar stocks paid back massively over a few months in 2013 which made up for most of my losses and put me in a good position for the next opportunity.
The energy market took a downturn in 2015 so I recognized that as another opportunity to invest in blue chips. In this case my strategy was on dividends in addition to share price increase so after comparing BP/ExxonMobil/Shell I settled on RDS.A stocks to play for the long term. I've made good returns on the share price increase, and continue to get the quarterly dividends. I'm getting closer to retirement now so my risk appetite and willingness to play in volatile stocks is much lower. I'm mostly riding on the profits I've made and the dividends I am continuing to collect.
So my limited success isn't really due to a brilliant strategy or extensive experience. It mostly comes down to recognizing the obvious fact that blue chip stocks recover from market downturns so they make a good opportunity if you didn't get burned by the market downturn.