Both of these images are great.
The first image of the subject on the water ski is fantastic because it uses a limited number of photographic elements to achieve it’s goal.
The feature I love most about the image is your use of a “leading line”. You likely are not at that point in your readings yet, but a leading line usually comes in from one of the bottom corners of the frame and helps guide your audience’s eyes towards your central subject.
For example roads are common leading lines.
http://static.desktopnexus.com/wallpapers/29180-bigthumbnail.jpg
Here is another example of using a crack as a leading line:
http://rickjennisch.typepad.com/photos/uncategorized/2007/07/11/0021_2.jpg
Leading lines are also great because they help provide the illusion of depth since they usually start in the foreground. This gives the illusion of 3 dimensions in a 2 dimensional photograph. Not only that, but they generally give the audience the feeling of “being there”. Great work on this image.
Your second image is also fantastic. In this image, your focus was placed on color control and simplification. The striking red bird against the green background creates a very dramatic composition.
The only thing I would like to see you experiment with is your object placement. Try to remember the rule of thirds and place your objects to one side of the photograph. It will lead to more of an informal balance create some drama in each of your shots.
Again, great work!