Agree, sconces are hung too high and you need something to fill in the space. Bobbi suggests art…great. For another choice how about the Moravian stars?

Would you consider changing your sconce to a downlight? I don't believe two lights work well on the bedside - so if you do want a candle, can it be a very small votive candle rather than this one that takes too much space, Instead add a tall sculpture, a pile of books, hang a picture frame etc etc

Not sure two lamps are needed on the iron table. I would have put the lamps on the nightstands, except for the wall lights already being above. I don't think the hurricane lamp containers are working there. I like bobbi's idea to stand some artwork on the back of the nighttable, or hang a couple of square artworks on the wall below each lamp.

Maybe some vertically placed mirrors. There are lots of pics on houzz usually with a lamp in front but here behind your lantern.
http://houzz.com/photos/355808

First, I must say what a beautiful job you did on the renovation of your bedroom. The recommendation I would make for the nightstands is to collage some pieces together. I like the candle holder but not directly under the wall sconce. Move it to the outside edge of the nightstand and pair it up with a small painting leaning up against the wall or hung slightly over the table. Then, group together some colorful books and a floral. On top of the books, add a small figure or box. This will give you color, dimension and texture. For the other nightstand repeat this in a mirrored layout however, switch out the books and item for a picture frame(s). Enjoy your beautiful room!
Picture via A Beautiful Mess

Love your bed, wall paint and windows......sorry to say the sconces just don't work......take those away and find a pair of large lamps to balance out your headboard, look and read in Houzz for ideas on size, shape, etc.....what you have now does not compliment your room or beautiful bedding.......it will be easier to find a pair of lamps, than to be eternally looking for the right combination for your side tables.............good luck

Or perhaps larger sconces: [houzz= http://www.houzz.com/photos/2288621/Dune-Large-Wall-Sconce-modern-wall-sconces-other-metro]
[houzz= http://www.houzz.com/photos/2822385/Sweeping-Taper-Large-Wall-Sconce-modern-wall-sconces-other-metro]

I would go one further on the mirror idea: have a glass shop cut out a round piece at the upper end of 2 rectangular mirrors: leaving enough space to reflect the image of your sconce, then adhere to the wall making sure both sides are level. The Beverly mirror from Home Depot would probably work well.

http://houzz.com/photos/603482

I agree with guru I think the mirror idea is great plus it will make the space look even bigger

Thanks everyone for all the great suggestions. Would anyone have any suggestions as to alternative contents to the candles for the hurricane lanterns?

Given the colours in your room, I would fill them up with a very fine grey/brown sand and then add a white coral piece in them (sustainably sourced of course)

You could fill them with river rocks, dried flowers, or small mossy stones.

Try a small orchid in a small pot. Stunning! And the glass walls of the lamp will support the orchid.

Don't like the sconces at all.... move one of the matching lamps off table. Nice bed.

http://houzz.com/photos/6529379

Shells perhaps?

http://houzz.com/photos/6120241
Spheres?

Vase with flowers, a small print, books

Don't burn petroleum based candles, they are unhealthy. Soy or beeswax are better. The flowers idea rocks. The area needs tall things, maybe models of buildings, like the Empire State Building and the Eiffel Tower. Or a jewellery tree. Or tasteful nude statues to add spice. Not Spice girls. ( Sorry if you were in the Spice girls. ) Prefer the Gilmore Girls myself. Rory's boyfriend gave her a large model rocket as a love gift. Now that would fit...

Hubby says fill the hurricane lamps with M&M s

i would hang either some mirrors or thin, tall art.
leave the hurricaines, i like them.

This will be an inexpensive way to make the sconces look like they are part of the vignette. Fill the hurricanes with soaps and move to the bathroom counter. Try a pretty silk floral arrangement on her side and a tall, interesting clock on his bedside table. These are pricey but posted for concept.