Accept that coins can go to zero, and even good coins can lose up to 80% of their value (especially against BTC). There are many coins that didn’t make it to 2018 that were once highly valued and popular. Meanwhile, even some giants of today like ETH and XRP have seen their value in BTC prices drop to depressing levels. You should prepare for this mentally and have a strategy that factors this in. If you buy the dip in ETH from .15 down, .08 may look like an excellent price, but you have to be ready for .02. ETH holders who didn’t prepare for this had a depressing June 2017 – December 2017. Heed my warning, that new coin doesn’t have to moon twice, it can go to literal zero, and even those that will moon again… they can have long seasons of stagnation in between (where they lose value against BTC for months on end). See the Crypto Graveyard and please look at the historic charts of major alts like XRP (the gap between moons is real and some coins really don’t make it).
Only invest what you can lose. During the recent crash in January 2018, hobby-investors got burned. Reports of frustration and losses came at the cost of broken monitors, smashed laptops, and heavy monetary losses. While the rules are in more particular order of importance, it’s safe to assume that this is the most important rule, the rule to rule the rules. As soon as your money is converted into cryptocurrency, consider it lost forever. There is absolutely no guarantee you can get it back. Losses don’t simply come from dips in the market; extraordinary factors such as hacks, bugs, and government regulation can mean you’ll never see any of your money again. If you are investing money you can’t afford to lose, you need to take a step back and re-evaluate your current financial situation, because what you’re about to do is an act of desperation. This includes: using credit cards, taking out mortgages, applying for loans, or selling everything and traveling the world (as glamorous as that sounds).