Always have a plan before you enter a trade. If you are in a trade and don't know what to do then get out! The very first part to your plan should be to determine your mental stop loss. How much are you willing to lose? The only thing you can control is your loss.
I am working on cutting losses quickly and not taking gains to quickly. If it hits my target price, but looks like it can go up then I am going to take off half and then hopefully make a higher profit on the other half.