YSK: Double tapping the search icon in many apps will take you to the search bar.
Many apps, such as Wikipedia, Google Photos or Spotify, have a tab at the bottom, with an icon to go to the search page. You then have to tap the search bar at the top to actually start searching (taking your finger from the bottom, to the top, back to the bottom half of your screeen).
To prevent this, you can double tap the search icon, which will bring up the keyboard.
Why YSK: Its a simple trick that will help you cut down on needless taps and stretching fingers on bigger phones.
I don't know if this is common knowledge or not, so putting it here for those who don't know. Might save some seconds of somebody's life!