Without proper backtesting-papertrading and money&risk management, just jumping on the trade. Also valuing other people's ideas and advices more than my own research and ideas.
Paper trading is the most helpful in my opinion because you gain the much needed experience to trade without the added risk of losing real money. I think my biggest mistake is I didn't enter the market really early.
Learning things deeper before investing huge amount of money into this business.
It helps a lot when you are preparing yourself, using virtual account and practice everything before dealing with it using your real balance, the
more you understand the market the more chances you are bringing to your investment, A very common mistake that most if not all traders has been done while working into this venue of investment..
to understand the market we are required to practice doing transactions often so that we will experience problems and success in every transaction. that way we can evaluate both of them, so that over time we become more adept at trading. and we must be able to enjoy the process, because every professional trader would have done the same thing before