Which is the easiest way to enable/disable Wi Fi, Bluetooth, GPS, Data connection or change audio profiles in Android ?
Answer is simple. Quick settings of the device. Current Android users can access the quick settings by swiping down from the top bar. Notification panel will open where you can enable and disable all above mentioned functions.
If you want second option to reveal quick settings, click on left menu icon on the device (from home screen). Quick setting options will open along with launcher settings (Works in selected launchers only).
When coming to Android 5.0 Lollipop, things are a little bit different. When swiping down from the top bar, initially you will see an option to change the users as Lollipop supports multiple users at the same time including Android wear.
At this moment, just swipe down again from the top of the panel to see notifications and quick settings. Now you can access them as well as other system settings like apps, battery, security, backup etc from the settings icon displayed on the top right side.