If your watch app has good VoiceOver support, chances are you'll also have good Assistive Touch support. But an improvement you can make is to implement a quick action (triggered with a double pinch) when there is a main action you can perform.

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Assistive Touch for the Apple Watch works like magic. It lets you use your watch with gestures with the hand of the same arm you are wearing your watch on. No need to use your nose! If you don't have it on, is because you don't know about it.

If you need for a view (and all its subviews) not to be focusable by assistive tech like VoiceOver, you can set its accessibilityElementsHidden property to true. This isn't needed very often, but it can be useful for certain custom experiences.

Sometimes your UI will just not scale for large text sizes. Simple changes, for large sizes, like disposing elements vertically instead of horizontally, reducing the number of columns, and allowing more lines of text, can do the trick most times.