No stoploss
getting greedy.
Invest very little money with weak risk management
…not learn and practice well before you start trading live.
Biggest mistake you can make is not recognising that odds wise no trading system with a decent RR is that much more than 50:50. The best systems are about a 65% wr for the most part and the expected value calculation includes (winrate x amount won)-(lossrate x amount loss) and that means if you can’t influence the winodds by that much then focus needs to be on the amount risked.
Your risk reward ratio, along with scaling positions, is by far a retailers biggest mistake. Small-Ball it. Take small risks initially with a position and scale up if the market confirms it is moving in the correct direction ensuring you have a very good RR ratio. Winrate means next to nothing, it’s always just over a coinflip with a good system, so focus on the other bits!