$GTC 15-minute plunge of 4.52%, current price 0.2471, 24h range 0.2291–0.2653.
A valid breakout is often accompanied by rising volume, while a false breakout often comes with little volume. This is the method I use most often to judge them.
When bulls are shaken out, the price often drops sharply and suddenly. But after the shakeout, it often rebounds.