For trading, I try to stick to a system/plan and stick to it. It helps to take the emotion out of it because there are set buy and sell points rather than doing it by feeling.
That is right, sticking to a trading plan is one such ways to put a check on emotions, but by saying a trading plan, it doesn't mean just about anything goes as sticking to a strategy or trading plan that is a sure loser, would only exasperate a trader's already battered emotions.
Another way to check emotions in trading is by deploying a bot tailor built to trade some strategies a trader is conversant with. Most traders have dashed their trading expeditions for using generic bots, they knew next to nothing, what it does or how it goes about trading. Before you surrender you trading account to a machine without any form of emotions, you may want to be sure you do not hand over total control to them.