You have done extremely well as a novice to capture this shot and keep the focus sharp. With more pracice you will be able to perfect your cloning technique.
You could add further impact to the shot by decreasing the depth of field, this would make the background more blurry and focus more on the windsurfer.
This could be achieved by using a lens with a longer focal length ie 400mm, also by opening the aperture as wide as possible
In photoshop this can be achieved by making a selection around the sail and the background and under 'filters' selecting 'blur' and then 'gausian'
Well done, as sports photography is a subject that many more experienced photographers find difficult!