Emotions emotions emotions! Impossible to get rid of them... maximum you can do is to learn to control them. Sometime I make the same mistake even though i'm not a novice trader. But i'm still working on myself 
My advice (what's working for me).... write your set of trading rules on a piece of paper and stick it somewhere in front of you!!! Sounds stupid, but works. At a minimum you should three things.
1. where you will fix your profit (i'd say the profit potential should be at least twice as big as the loss you are willing to tolerate).
2. where you will fix your loss (do not less losses run).
3. reason for entering a trade (make sure the reason is not an emotional factor).
... and stick to your piece of paper!!!
My advice (what's working for me).... write your set of trading rules on a piece of paper and stick it somewhere in front of you!!! Sounds stupid, but works. At a minimum you should three things.
1. where you will fix your profit (i'd say the profit potential should be at least twice as big as the loss you are willing to tolerate).
2. where you will fix your loss (do not less losses run).
3. reason for entering a trade (make sure the reason is not an emotional factor).
... and stick to your piece of paper!!!