The new iPhone 6 Plus includes a unique keyboard that appears when the device is held in landscape orientation, and it includes left/right cursor keys at the top right. These move you back and forth one character at a time through text.
What’s less obvious is that if you double-tap the Shift key, to enable Shift Lock, the cursor keys will instead highlight text when you tap them. Give it a try. Sadly, this doesn’t work if you hold down the Shift key with one finger and tap left/right with another.