The mistakes that newbies mostly make is think that they can skip the learning process and jiust begin trading. Trading has been simplified and it is a matter of just buying and selling on a graph. If you do that then you are just playing with luck and it may or may not go bad for you. You need to know and not just practice.
Making mistakes is normal. You don't need to blame yourself for it for a long time; you need to reboot yourself quickly and move on. You may want to take some time to analyze your mistakes and enter the trading log. You should also review your trading strategy and learn how to manage your capital correctly so that your account does not collapse in the future.