to me the the 5 things that all trader should do are as follow.
1.. every trader should do trade in such items in which he as some good knowledge about it.
2,,,, all trader should invest such amount of money which he can easily bare to lost.
3.... all traders should avoid trading on loan.
4..... traders should try to trade for lonng term.
5.... traders should invest in trading according to his experience.
Every trader should know that some coins really has good potential and rest of it just useless coins which maybe pump once and then dumped for good. Every trader should develop their sense to choose the best coins, such as monero when it was $20 few months ago and it reach over $100 righ now. Some coins will be profitable if you can be patient as long as those coins really has usability instead of just for trading purpose.
That is the main thing should traders do in their beginnings they should learn how to choose which coin is the best to buy and what it is the best to buy in the market. It is useful or it is just for trading purposes. Every trader should know the difference for that and if they will become a good analyzer for the different coins out there then they can easily make profit.