Watch DOW and S&P charts

On Friday I entered a position in PMCS and saw it break supports and head lower before rebounding at the end of the day. I then pulled up the DOW chart and saw that it mirrored DOW minute by minute. The entry was impulsive and fortunately I am not a huge amount with such lazy entry. My charts were not set up and I didn't follow any method but just took a position.
 In hindsight it would have been better to watch the DOW and figure the day's trend and either stay out or short when it was going down instead of blindly jumping in when most of the stocks in my watch list were heading down.