Uh, I still suck at this (letting winners run that is). My losses are no problem but I set mental profit targets which get in the way of letting a real winner run. But better safe than sorry. Currently, for as many that I got my target from that just kept going after I got out, there are just as many that turned around and took me out BE or a little over. Experience IMO is the best teacher - some ideas I have started to use in my logic:
1. If combo of Nas, Dow, and SP all in solid green = hope that the winner keeps going and maybe stay in overnight. All red = opposite logic for shorts.
2. If combo of Nas, Dow, and SP mixed or no clear red or green area = set targets and use them.
Its simple but I am still experimenting w/ how effective it is.
Mike