Are your iPhone photos out of focus or the wrong bit of the photo is in focus? You can set it really easily when you are in photo mode and ready to take the shot, then tap on the screen on the bit that you want in focus and a square yellow box will appear and that is the area that will be in focus for this photo.
But also take note that a sun will appear beside the yellow box that you can move up or down to affect the light and shadows (exposure). Try taking the same photo but just change that sun position and you’ll see the difference.
Another trick is instead of just tapping on the screen for the bit you want in clear focus, tap and hold and you will see the words AE AF Lock come up on the screen, which means that the focus is locked, it doesn’t matter if someone moves in front of the camera or if you take a photo it will stay at that same focal length that you initially set. Until you tap on the screen again or change to a different photo mode.
Share the knowledge, and see tip#16 for daily hints.