The common mistakes and problems of a trader is the fear and their emotions in trading if they did not control their fear and emotion then they might sell it even not reaching their price goal and they might buy coins even it is at pump that is the common mistake they make.
A wise person once said, to get win first thing is to overcome your fear in any field. Implementing here, definitely a newbie or even some experience people often get afraid of starting something new. This let them undergo a phase where they dont come out the box. Their thoughts become limited and they dont try to be creative in that environment which must be broken.