Own those stocks before they go up a lot, sell before they go down a lot. Not being snarky at all, that's actually the ideal way to take advantage of it; it's very difficult to time properly, and difficult to know which stocks will ultimately hyper-perform and which will not. For example, Upwork (UPWK) isn't participating comparatively much at all, while Overstock goes up ~3,900% bottom to top, and Fiverr goes up ~500% (disclosure: I don't own any of those stocks). Who expected Overstock to go from $3 to $120? It's wild speculative behavior by investors, a feeding frenzy pouring out of the boom in Shopify's stock (along with the relevant aspects of the pandemic, including online ordering). In general the best bet for an average investor interested in taking advantage of the insanity, is to not try to perfectly time a top or bottom - if you catch a wave, accept good enough and get out, instead of reaching for the final pennies on the table and riding it back down.

Generating large returns has been easy for a while now. You have to retain the self-discipline to remind yourself that getting 40% in a day is ridiculous (as with Zoom today), that in normal times that is two or three years of good returns. It's about consciously restricting your own reach for greed. Average investors that get lucky in bubbles also tend to get crushed by them as well.

As an example, back in March I posted my thoughts on buying during the crash and I was buying Square in the $30s at that time. I'm out now. If Square goes on up to $200 or $300 per share, I simply don't care. My returns were easy, ridiculous and good enough, I sleep extremely well having exited with the gains I generated. They're mine now, I captured that return, locked it in, and that's the single most important thing. It's a far better thing to secure already massive gains than to reach for more, being greedy, and risk all of it if the mania turns south (which it will at some point, nobody knows when though and trying to pinpoint that is most often a fool's errand). Always have the discipline to walk away if you hit a homerun. The crazy returns (ie anything far beyond reasonable, very outsized) generated at this time are mostly not skill, they're luck; spotting a position to enter can be skill from years of mental training, however getting 500% on eg Fiverr in five months is mostly dumb luck (to be clear, it's the particularly outsized return that is the dumb luck part of that); cash that luck in, as it will inevitably turn against you.

There are some very straight-forward moves an average investor can make to shield theirself as well, requiring no particular skill. For example if you generate a large return quickly in this market, remove the initial principle, maybe a reasonable chunk of profit as well, and let the rest ride if you have a strong desire to continue to participate. Mentally accept that portion as money that may very well go to zero, to emotionally steel yourself for a bad outcome if the market crashes at some point; that's your speculative money in this gambler's market, having safeguarded the other portion. If you care to, you can even constantly peel your principle back out of these stocks as they climb, rather than aiming for a particular high point to sell in bulk (and trading fees are widely now zero, which can add-up in that context depending on the position size). Losing a big chunk of your principle investment generally stings a lot more than losing a big chunk of some easy outsized gains, always keep that in mind. It is most often easy come / easy go in markets like this one, and the only way to avoid the easy go part of that is to exit the gains at some point.

You might see a lot of people saying the market can't go down because interest rates are so low / zero. Interest rates have been between very low and zero for a decade now, and they'll probably be low for a long time into the future. The market can return to its former multiples from eg 2014-2015 (when rates were also de facto zero), while rates are at zero. Don't let yourself fall for that premise, as though this market's extreme upward trajectory is guaranteed. A crash just back to the multiples we had in 2014-2015 would hammer this market, taking it down by 30-40% (and the more bubbly stocks would particularly get smashed).