Failure to identify the right sources: We live in the golden age of communication, and even though that has grossly benefitted us, it also comes with its own pitfalls. Investing and trading is all about accessing and evaluating the information to the best of your knowledge as a trader and/or investor. With an overload of information today, your job is to identify those sources that resonate with you from a risk vs reward standpoint and veracity and legitimacy.
Leaping unprepared: Markets are extremely dynamic in nature, and with information and education, practicing in a live market is the key to building proficiency and tenor. Use simulators and/or sand-boxes in abundance to build your confidence, get feedback on your conceptual understanding, and accordingly, prepare for the world of stocks.