Regarding the OP:

This is a major concern of mine, too.

A major way to shield one's self against a bubble is to avoid buying during a mania (normally a sudden spike in price that's the result of a lot of people trying to get in on a "sure thing") and instead buy sometime after a panic (a sudden drop in price that's the result of everyone trying to dump their assets because that "sure thing" wasn't so sure, after all). However, there's more to it than that. Diversification also helps. Not just diversification of one's cryptocurrency portfolio, but also other assets (having some percentage of your portfolio in precious metals, perhaps just enough real estate to live on, maybe even a gun or, Hell, some stocks, to name a few examples).

In addition, try to pick coins to invest in that will likely survive a bursting bubble and government regulation of the marketplace (both things are coming, mark my words). Privacy coins are the most likely to survive, and even thrive, under government regulation, so I'd diversify into (or even exclusively own) privacy coins (Monero and SpectreCoin are two good ones that I know of; Monero more from reputation than anything). However, there are other coins that I think could do well, too, some that aren't privacy coins (though those coins would likely only do well in places that didn't experience a government crackdown). Bitcoin Cash and Litecoin, for example; they're both "better" at being used as currency than Bitcoin Core is right now, largely because of transaction times and transaction fees, which means they have some good staying power relative to Bitcoin Coin over long term.

The main thing, though, is to not do what "everyone else" is doing. Whenever "everyone else" does something it almost always ends up hurting "everyone else" to the benefit of those who decided to be individuals and not follow the collective. That is, did you sell during a mania (huge price spike because everyone wanted a "sure thing")? Well, you're going to do really well after that price spike corrects thanks to a panic selloff (at which point you'll be there to buy their product at less than what you sold it for to "everyone else"). Try to avoid "catching a falling knife", too; you're guaranteed to get cut, even if it's just a little bit.

As I mentioned earlier, you share a major concern that I have in regards to this bubble (which I don't think has actually burst yet, we're just experiencing a minor correction right now, not a bubble bursting). I hope we can protect ourselves from that bursting bubble when it comes. Best of luck, man. :-)