With flash fiction, imo for the best chance at making it interesting, something small and off-beat, something different, unexpected, a little over-the-top. It seems the flash stories with the "Big Moments" in life are most likely to be boring. Unless you do something unexpected with them, then keep on twisting.
The minister said, "You may now kiss the bride."
The groom [put in strange action here].
The bride (or someone else) [put in strange action or dialogue here].
Rinse and repeat.
Flash fiction is fun to play with and delightful imo when it goes in a way that is unexpected.
Those are just a couple of possibilities out of many but most of the flash I've seen that imo wasn't very good was, to me, too straightforward. With such a tiny space, you need to have something much more snappy than if it was just a short scene in a novel.
Also, one idea for tying it together is at the end, go back to the beginning, if you get stuck on it. Perhaps even repeat a line that was said at the beginning, or repeat an action from the beginning or the opposite of the action.
Reading a bunch of flash fiction is a good way to get a feel for it, too. Good luck.