To me, they look too “arranged”. A large glass bowl filled with the lemons in a more natural way might look better. I’ve used fake fruit in the past, but prefer to use fresh, or skip the fruit altogether. How about a live potted ivy surrounded by three matching candles?

I like the lemons too and the height variation, but I think you need to add more around the bottom of the piece, not necessarily lemons, though. Maybe sprigs of rosemary, sage, or other herbs along with forsythia or other flowers. A lime would be fun, too. I also think I would prefer the candles to be not enclosed in glass, just the pillars alone. Maybe try a pale green pillar rather than ivory?

what about a wooden barrel jar instead of vase?
the rustic look with the lemon can be amazing together
i have something similar

I think that everything you do in decorating should make sense. There should be a purpose to things, and I see no purpose to have a group of lemons together on a dining room table. Ask yourself, why would lemons be there? and I think you'll see that there is no reason for lemons to be there. If you're wanting to work with what you have already started, then I would ..... get a larger and a square tray (round trays on round tables look like you're doing cake layers). Then I would get 2 more glass cylinders so that you end up with three in varying heights. Then I would fill them with decorative objects. I would remove the candles. Get a larger and more visually interesting/unique tray.

I think you could arrange them a little more simply. We have a lemon tree and I like to display them with their stems and leaves attached. Sometimes I arrange them on a cake stand, and sometimes a wooden tray or bowl. I usually don't have them in a single layer but kind of stacked with the stems/leaves protruding. I often clip them off the tree in clusters.

The real ones actually last quite awhile sitting out, but we do have the tree when I need more...and more from the tree.