Great picture! I would cut some of the wall off the top to start with! It is kind of fuzzy, so I would sharpen it up a bit, and I would adjust the levels to give the picture a bit of contrast! Especially since they are wearing black and white!!! Hope this helps!
 

For what I see...the pose is fine but the lighting is the problem. At least on my screen you can't see the eyes and that is a must. Some fill flash was needed. There also seems to be a little too much space at the top and may be cropped a little short at the bottom. The cut off flowers do bother me some as well.
 

I think this is a great shot that is very natural palette. I would simply run a defog ( contact me if you don't have that actn. created). Then I would goto img-adj-level and increase far right input slightly till satisfied. u cand try these out till u see what you like. Flatten Image and then do a very transp (10perc.) and 0pac either 50r 6 i would use a dark color and just go around the adges until you see the pop!! Thats it! U can also for a final touch do unsharp mask very slighty to smooth out the pic!

Whole process takes about 5 min. You van contact me if you would like a copy of some of my actions. They are free!! After all we are all trying to make it in this industry, right. I am open to any tips I can get.
hunterms0513@gmail.com
 

I also agree with the other critiques- the picture is a bit blurry and the eyes too dark. Using a tripod and/or flash would remedy that. I'd either crop the flowers completely out if this is your original, or if you have an unedited version, crop the top some but keep the flowers in.