if we let ourselves carried by our emotions, then it will not lead us into our goal but rather pull us down and commit mistakes again. Although being emotional and even greedy when it comes to investments profits, is a human inborn but if we start controlling it then somehow we can minimize committing mistakes and losses.
For me, the best advice i can give is to set a target price when to buy and sell. If you have your plan and definitely your goal, then even if you are struggling to control your emotions but as long as you stick to your plan then you will never be in a huge loss.
That target is the thing that makes the difference between a newbie and a veteran. I know that there are more things that makes a person a veteran, but as long as you do not have a target when you get in, you will always be a newbie. So, it is like all thumbs are fingers but not all fingers are type of situation where if you do not have a target you are definitely a newbie but if you have a target that doesn't mean you are a veteran.
When you get into any trade at all, any investment, any income bringing thing that means you need to know when you want to get out, even if it is a million dollars then you still have to know what you are doing and act accordingly, without that then you will always be running around not knowing what you should be doing and that will result with a loss 100% of the time.