Center piece

I feel like they’re cute, but maybe add more flowers to them so they look fuller. I’d also suggest either a neutral container or a more muted flower base. The blue planter with bright flowers seems busy

They're super cute!

I agree with a more neutral fower pot/vase and perhaps some greenery? Or additional flowers to fill out. If you're going for blue, hydrangeas might be nice as they take volume without having to use so many stems. Out of curiosity, are your colors blue and peach/coral?

I'm struggling with the same thing and have been told to "fill it in" a bit. I went with clear glasses I picked up at the dollar store, and I'm adding some small colored light strands to make it interesting. I suck at crafts, but I'm learning by listening to others and looking at their examples. Your colors are very pretty.

I think it needs a bit more-maybe lower smaller flowers to fill a bit or greenery/leaves?

I think it just needs to be a bit fuller. Maybe add some filler greenery or baby's breath around the bottom, so you don't see as much of the stems?