Something that I have discovered that never fails to put a smile on my wife's face is when I do a routine household chore that she normally caries out. If you have a chance, find out what daily tasks your wife dislikes the most then try to do it for her when she is not expecting it. For my wife it is laundry and cleaning the bathroom. On different occasions I have done the laundry or cleaned the bathroom while she was out of the house. Even if you can't get her out of the house to surprise her, just pick up and do it and I'm sure your wife will be blessed also.
I will admit sometimes I don't recognize all that my wife does everyday, but even a little effort in relieving her of a simple task makes her happy.
And you gentlemen out there might think... "Well if I do this once she will expect it everyday". Thus far I haven't found that to be true. Generally, my wife has expressed that it makes her feel loved and noticed, and makes her feel more inspired to keep doing all of the ordinary things in life.