It also looks like there is some camera shake so a tripod or some kind of support will help improve the quality of the shot. I also think you should clean up the background a bit or chose a background with less distractions if you can't get a shallow depth of field. I'm not sure how much effort and time you two want to put into this production, but dressing up a little and posing can also improve things (horizontal strips are unually not very flattering).
Here's a website filled with tips and videos on taking portraits and looking good in pictures:
http://www.lookgoodinpictures.com/
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