When buying altcoins, I always follow a principle:

Leadership thinking.

Don't rely on the theory of compensatory rise. The leading coin can continue to rise, getting stronger and stronger, and has an obvious blood-sucking effect. On the contrary, those junk coins that compensatory rise often show up in the later stage of the market.

Another method is to observe which altcoins are the most resistant to declines during each callback. In this wave of rebound, the strong altcoins have recovered to the high point before the waterfall, while those weaker coins have never been able to go back. Choosing the wrong coin is like choosing the wrong partner, even bottom-fishing will not help.