1) Don't blindly trust signals, take your time to access and verify it.
2) Do your own research(DYOR), coz it gives you confidence and control.
3) FOMO and panic selling are dangerous. Rather be patient and disciplined.
4) And lastly, Don't Invest more than you can afford to loose.
Any trader that can avoid any of the mistakes that you mentioned won't have a hard time making profits from trading. For the individuals that are blindly trusting signals groups are setting their own selves up for a big disappointment in the future due to having trust on people they don't know that can scam them by giving them signals to buy their own created cryptocurrency then make an exist scam on them. You can't be successful in trading without making mistakes therefore you shouldn't be afraid of making mistakes but always learn form that mistake that you made so that you can become a better trader.