The Apple Watch uses an OLED display panel, wherein each pixel generates its own light. Using a black display on OLED would simply switch off the pixels. With this, the black space on the Apple Watch face would use less power, compared to the solid colours and bright whites. Also, try reducing the display brightness that aids in saving energy.
TAKE CALLS ON PHONE AND NOT WATCH
Answering calls or using Walkie Talkie features on your watch consumes a lot of power. Although a short call of five minutes wouldn’t impact the battery much, it is best recommended you use your phone for taking calls.
USE BLUETOOTH LE INSTEAD OF WI-FI
Apple has specifically designed the Apple Watch to minimise energy consumption that uses Bluetooth LE (Low Energy) for communicating with iPhone. In case this feature is disabled, your watch would be forced to use Wi-Fi that consumes far more energy.
REDUCE OR AVOID HANDSFREE MEDIA PLAYBACK
Streaming music services like Spotify or Apple Music on your Apple Watch eats up a lot of power and quickly drains the battery. It is advisable to use an iPhone if you use these features and want to conserve more battery power.
USE POWER SAVER DURING WORKOUTS
Apple Watch comes with the ability to monitor your heart rate while exercising but not everyone uses it. Disabling the heart rate monitor would help you save some battery and the Watch will only track metrics like speed, distance and time while working out. For disabling the heart rate monitoring feature, open the Watch app on your iPhone and click on ‘Workout’, followed by toggling on the ‘Power Saving Mode’ on the next page.