How to Take charge of energy-saving settings
Go to System Preferences > Displays and move the Brightness slider to the left to turn brightness down. Uncheck “Automatically adjust brightness” to stop it going back up.
Quit unused apps
Click the battery icon in the menu bar, and look for the “Apps Using Significant Energy” section. Quit unused apps to ensure they’re not eating up CPU cycles when you think they’re idle.
In System Prefs > Energy Saver, you can set how soon the display goes to sleep when your Mac is on battery power and left idle. The faster you set this, the more power you’ll save.
Tame online content
Browsers are culprits for high energy use because of poorly made ads. A content blocker will save you battery life. In Safari, go to Safari > Safari Extensions. Try the Ghostery extension.
Wi-Fi and Bluetooth
If you don’t need Wi-Fi, turn it off, as it uses power even if inactive. Do so from the menu bar icons, or in System Prefs’ Bluetooth and Network panes for Bluetooth and Wi-Fi, respectively.
On MacBook Pros with two graphics chips, enable Auto Graphic Switching in System Prefs > Energy Saver. If not, your Mac always uses its power– hungry discrete chip.