Below is an example but the basic idea will be the same for most photos. Best thing to do is try it. But as always, check your camera settings and put everything to the biggest size, resolution, quality. It is important.
The reason for this post to to get you to take more of the surround / area about the subject of the photo. Rather than just getting close and taking the photo, try and move back and then take the shot. It's easy to crop off parts of the photo you don't want later, hard if not impossible to add to it.
Have a look here, what looks like a perfectly taken photo. You get down low, take out your phone, open the camera and frame the kid nicely in the screen...
Okay, not much wrong with it, but lets see what could have happened if we turned on cam and stood back a little. (remember, we can always crop it later)
Now, already a better composition. But lets see how it would have looked if we placed the baby slightly off center.
I think you agree this now is a much more interesting photo. Compare this to the first one. See the difference and all just done my holding the camera / phone sideways, not being so close and having the kid slightly to the right.
And lastly, and this is another reason why it's so important to have the camera setting set to their highest, lets see what happens if we zoom in and make the photo black and white .....
and now make a canvas print of it.