Rule number one of investing; Don't invest more than you can afford to lose.
You should go into this ready to lose whatever you put in. Ultimately, as the price swings up and down, you should remain calm and still be living a healthy life with a room for regular spending.
I've heard countless horror stories of people investing greedily with their entire life saving or borrowing large sums of money.
This is a HUGE mistake.
1. You invest your life savings
2. You don't do your own
Research a coin before you invest in it.
So many people invest based off of hype. They see other investors on Twitter or Facebook talking about a coin, see the coin's price rising, and then buy off of impulse. This often ends badly.
Do your own research.
If you want your cryptocurrency investment strategy to profit, you have to sell and accumulate profits eventually.
Learn from others mistakes. At the end of 2017, during the big boom of cryptocurrencies, lots of investors became rich if they sold for profits. On the other hand, many had theoretical profits but overheld into this bear market. Now, they are stuck holding at a loss, waiting for the next bull run.
Remember: You don't profit until you sell back to realize your gains.
3. You don't take your profits