On Apple’s keyboard, you can type symbols, etc. very quickly because the modifier keys work just like a real keyboard. For example, when on the letters keyboard, hold the 123 key with your left thumb, then tap any character with your right thumb. You can even swipe from the 123 key to any character. These gestures also work with other modifier keys, including shift and ABC.

Plus, you can double-tap shift to enable caps lock, hold space to enable trackpad mode, double-tap space for a period, and hold many characters for secondary characters.