Keep these things in mind...
Is your lens clean? Wipe it clean first!
Don't zoom in. Move closer to your subject and crop later. It will take a higher resolution photo. We can crop it later.
Photos are always better with good light... Natural light is best! Step outside or near a window. If you think about this before you take a photo, it will pay off!
On the phone, tap on what you want in focus.
Don't use a filter. Send the original photo first. Sometimes filters automatically lower the resolution and size.