Table number - I’d suggest something the give your centerpiece some height! Levels are really pleasing the the eyes ( attached a pic but doesn’t need to be that style) More lighting - either a candle or votives or mini led string lights
Ok, how about fill the smaller jars with just enough water to have a floating candle, and then if you're having table numbers, use those tall thin wire holders just to give it a bit of height and won't block the jars?
Pinecones could be nice too just loosely laid around the jars to go with the more rustic theme, and you can add some glitter too if you felt like jazzing them up a bit.
You could also buy some more greenery to beef the look up and fill in the space between the jars a bit more.