The poor colors / presentation of your JPEGs can be traced to not using sRGB when creating your JPEGs for posting. Using AdobeRGB or ProPhotoRGB is fine for editing images. However, you have to change to sRGB when creating files for sharing. A dump of the EXIF data of the couple from the initial post:

Color Mode : RGB
Color Noise Reduction : 25
Color Noise Reduction Detail : 50
Color Noise Reduction Smoothness: 50
Color Space : Uncalibrated
Color Space Data : RGB

This discussion provides a lot of detail, examples, and links to still more discussion: http://www.uglyhedgehog.com/t-364870-1.html

As you develop a standard process for creating your JPEG images for posting, consider this additional discussion of how to resize the images specifically for online sharing, http://www.uglyhedgehog.com/t-512745-1.html

Regarding the shot of the couple, I would turn the camera vertical, so that you show more of them and the bridge in the background. It is an interesting backdrop, and you should use it to your advantage. Here, it is cut off and when I look at it, I want to see more. The lighting is good and I like the pose as well. Regarding the 2nd shot, I like the repeating lines and their shape is pleasing to me as well. The shot is a bit busy though. When I teach basic photography to my students, I tell them to show ONE thought in the image. Keep it simple and if there's several "things", make several shots. I also tell them that if I can't look at a photo and tell you exactly what the photo is about in 2 seconds, there's generally too much in the frame. Simplify.

Unfortunately, Photoshop does not preserve the history when it is saved, so my working on it and sending it would not help. Fortunately, there are usually several paths to correction, so If I give you general directions, you can play around. That's the best way to learn, anyway.

Here is what I did. If you like it, use the Quick Selection tool to select you two, then Select and Mask to get a more accurate selection. All tools have tutorials if you google them. And/or, send me a private message (can attach photo) here if you have problems. After you get the selection, I will walk you through various steps.

You have enough info in your photo to fix it without reshooting, if you do post processing in Photoshop (or, probably, some other program) First I cropped and straightened, to emphasize what's important. Then, I selected you and your wife, adjusted color, contrast, and tones, lightened some of the darks around the eyes. I then switched the mask to the background, and toned down the saturation overall, adding a bit of saturation back into the river and some of the brighter leaves. I'd be glad to post this, or to PM it to you.
It's a fine shot of a good moment, and deserves to be fixed and shown.

I think you had some goals in your mind and maybe you achieved them to a large degree. We all have different approaches and constructive criticism isn't always well received and sometimes subjective, not always. Couple things I wondered about - you seemed to have interest in the background ie river etc and wanted that part of the picture, you were concerned about white balance and then mentioned rule of thirds for composition. I felt that a picture of you two is conflicted by emphasis on the background - just my opinion and you were shooting at f10. I might try a little more "blur" to the background although you are using an 18-55 lens. The idea of fill flash comes to mind in order to avoid raccoon eyes and brighten up the faces. Just note that you will have sync speed to deal with but in the shade, not a major problem as a rule. I might try shooting this at 55mm, moving your tripod accordingly. So, just my two cents since you asked. I've shot in similar situations and i think you did a smart thing by moving into the shade. Here is a pic I shot years ago with similar challenges with fill flash. Maybe not the best pic. also, big difference in the image that you was the download. brightness and color temp.