Jev
Always use a stop. If you use a mental stop you will be subject to an ill informed decision and at the whim of your emotions (Fear being the biggest!). You must rely on the info as you saw it when you were not in the trade and emotion free. Set a stop. If it hits it, move on.
You need a structred PLAN to trade. Discresionary trading only comes with vast experience. If you have no plan, again you are subject to your biggest enemy. Yourself.
Read 'Way of the Turtle' by Curtis. His mentors said that any trading plan could be revealed to Jo Public but only 20% of them would be profitable; the other 80% would not trade the plan and blow their accounts! Emotions take over.
Set other rules, like any more than 2 losses, walk away and come back tomorrow. If you can't abide by a simple rule like this then you should never trade as you will destroy your account. Reassess all the time. If you keep losing, go back to your trading diary and records and look for trends. You must make these records otherwise you have nothing to base your performance on.
Another good book well worth reading is 'Come into My Trading Room' By Dr Elder. He shows you a disciplined approach to trading that to be a consistent winner, you must have.
Don't get me wrong, I'm not there yet. I still have a lot to learn and emotions to master too. It's just it takes money and losses to find out.
Judge how good you are at trading, not on your wins, but on your losses. Keep a simple equity curve sheet and record your balance each day. If the trend is down you must re-assess your plan!
Hope this helps?
Grim