When trading there are rules to observe in other to protect your margin, it's more like if you can't make more money, don't lose the one you have,
That's where risk management comes in handy.
The strategies are;
_ Don't risk too much money, start with what you can afford to risk. Focus on the risk not rewards.
_ Identify potential risk as;if it goes down, if you don't take profit, if you don't use stop loss and if the coin goes against your analysis.
_ Reacting to risk, use stop loss and always take profit.
The third point you mentioned is the most critical one and this is where most of make the mistake.
We forget to take the profits and keep waiting for more profits in greed.
We don't realize that the profits are diminishing and end up selling in a loss.
We don't use stoploss because we want to give room to the trade and end up losing more than our risk.