first is patience,
patience is the main key to successful trading, because without patience we will often be stressed when seeing the market go down so fast,
the second is don't panic.
do not panic is the second key to successful trading, because if we often panic then we will also often cut losses,
and learning to control both emotions is the key to success.
Dude, you realize what you're typing is not the answer to OP question right?
- You take too long to decide when to sell off or buy
I don't think this can happen only because you're emotional, but it might happen too if you use too many indicators. Because of this, most traders recommend to use around 4 or 5 indicators in order to guide your trade (unless you're doing fundamental trading or long-term holding).
Btw, a tip to avoid getting emotional is to always stick to your plan. Sure, you might miss big gains but you can manage risk properly with that. Instead of hoping to get 1000% overnight, you should avoid getting rekt by 50%.