Right, I'm going over what you can do to improve the cow shot.

Some little pointers on post processing, use a levels or curves layer to add a little more colour/contrast into the piece, then use gradient maps and photofilters to add colour dependant on what you want to achieve, you can also use the Sharpen feature, burn and dodge (the highlights and shadows) and even blur filters for some photos.

Here's a rundown of what I did to your cow.

1: Leveled out the eyeline, there's nothing worse than having an eyeline or horizon tilted off center, ruins the balance of an image completely.

2: Used levels to create contrast & added photofilters for an added touch.

3: Used a reverse radial gradient (black) set to 10% opacity to give a lomo "darkening of the edges" effect, which rounds off an image really nicely.

4: Popped a little white border around the edges, and sharpened up the image.

5 minutes of work, and here's the result: