Quote from NoDoji:
It's human nature to avoid pain, and in trading that can be the pain of losing money or the pain of being "wrong". In a sim account you excel because your focus is on trading your setups. There's nothing "real" at risk and so you see your setup and you trade it. You're probably not afraid to hold through price wiggles, in fact you may hold winners much longer than you've ever held a live position.
Once you switch to real money, your vision becomes filtered by fear - fear of losing money, fear of being wrong. When you see the price action environment as "glass half empty", you notice things that have nothing to do with your setups and trade management plan. So you hesitate to take a position on a valid setup, then the position is working and you're not in it, so you may chase an entry which can ruin an edge. Or you take a trade and as soon as price runs a bit in your favor, you move the stop to break even because it's very comfortable to be in a situation where you can't lose money on the trade (but I'll bet you NEVER immediately cut short a trade that runs a few ticks against you; heck no we hold for the full loss!) Your b/e stop is hit and price starts running back in your favor and you chase back in, again diluting your edge. And so on.
There's no easy way to cultivate a trader's mindset once you've indulged in bad habits. It's a long process that involves feeling stress and discomfort over and over again, until the joy of consistent profits finally convinces you to just shrug your shoulders, hold your nose at the hard right edge, say "Here we go..." and jump.
Leap and the net will appear!