Quote from NY0BScalper:
If you're hitting your goal and then losing, the problem is not related to goal setting but to your strategy's performance in dfiferent times of day. It's best to take every setup, though if your setups fail after 11:30 except on highly volatile days, obviously you should stop... or risk less capital learning to trade different setups in different times.
What I do though, is tighten up. If my goal is $1000 and I hit it, I don't want to see $850 or less on my screen - when I do, I quit.