Hugest problem is learning acceptance. Those who constantly say "leaving too much on the table" is not acceptance and most likely will not be profitable over the long haul in day trading.
Find just one pattern you like and have backtested, then constantly work at exiting the market by what the charts are saying. But way too many are always jumping around from indicator to indicator, pattern to pattern, extending protective stops cause they can't take a small loss.
Make yourself a promise, if you can't do 13/15 days of being profitable in sim trading, you don't go to real trading.
Learn about Climatic Bars, and don't take trades inside of this bar's range.