I think a lot of new skilled day traders spot patterns in the current market and can make money in the short term, but then they get overconfident from their winners, and when the market conditions change, their strategies start backfiring in dramatic fashion.
For anyone wanting to begin day trading forex, I think the best thing to do would be simply to watch the market for 2+ years and wait until you've seen a whole range of different market conditions before committing a lot of actual money to trading. Focus primarily on watching the market and learning how price move on different kinds of days, and focus less on making money. During this time stick to just paper trading or trading small size.
Once you have developed multiple strategies for different market conditions and learn the signs for what type of market conditions are likely to occur that day, stuff becomes highly-predictable and it then just comes down to good risk management and execution.
Once you've been consistently having something like 80% to 90% winning days over the long-term, then that's the time to start focusing on the making money aspect more. Until then your focus should be more just on the learning aspect.
If your primary goal initially is to make money instead of learning about how pairs move, then it can be pretty easy to start thinking that winning trades are good trades and losing trades are bad trades. That's where new traders tend to run into trouble.