1. Use Limited Order
Never buy or sell at market price. If you do, think what could happen if your Sell at market price order was executed in the morning of August 24!
2. Stop-loss Order is Risky
A stop-loss sell order is executed when the stock or fund's price falls below your specified price, then it will be executed as a market price order.
3. Avoid trading at the beginning and ending of the market
The beginning and ending moments of the market day are typically volatile, avoid these periods if possible.