Being able to adjust your VoiceOver volume on Apple Watch for different situations is very important. I will show you two methods which I use.
Double-tap and hold on the Watch display with two fingers. Then, slide your fingers up to increase volume and down to decrease volume. Let go when you are happy with the volume.
I have found this to not be so reliable recently, but it’s still worth trying.
Find the Volume option on the rotor by twisting two fingers left or right on the display like you are turning a dial. After that, swipe up to increase volume and swipe down to decrease volume.
These methods are both quicker then opening Settings > Accessibility > VoiceOver > VoiceOver volume to change it, and they are handy to quickly change the volume.
If you have set the volume too low and you cannot hear VoiceOver, try Method 1. If this doesn’t work, your only option is to adjust the volume through the Watch app on your iPhone.