There’s more that more experienced photographers can put more eloquently, but as a graphic designer I have two immediate points of feedback:

• Editing wise I would up the saturation a bit, and a bit more contrast in the lighting.
• The framing could be better: the part of the flower seen on the right adds nothing to the composition and distracts. Cropping it off would be better.

Because they’re great to invite to a party!

No tips here but a photographer with macular degeneration is a special kind of horrible. My sympathies to your grandfather.