I think it's quite simple if you stick to certain rules while trading. Nothing complicated, but many traders very often ignore them:
— invest only that amount of money which you can afford to lose;
— never put all your coins in one deal;
— don't be greedy, don't invest mindlessly and avoid FOMO;
— if you have failed, learn from your mistakes, make some conclusions, and don't give up.
I saw some experts advising to track Bitcoin's behavior which is reasonable.
Also, if you've just entered the crypto market, you will search for a place of trading or buying. And I would advise you to take a closer look at CEX (https://cex.io/). It's simple for beginners and offers all major coins.