Congrats on a good score for your second challenge!
I don't do RAW and I don't know much if anything about converting, but I will try to comment on the other steps you mentioned in your comments.
I like the composition. Although I agree that a bit of a tigher crop on the right probably wouldn't have hurt, I love the overall shapes that the landscape and the reflection make. Your application of USM was good as I can see plenty of details but no signs of too much sharpening.
Hue and saturation look pretty good, although the shot overall looks washed out. I think that has less to do with hue and saturation, though, and more to do with levels or curves.
Pretty much always the first step I take when post processing is to use "auto levels" (in Photoshop). I may not always use the result, but it gives me a great idea of how the darks and lights in my shot should be balanced. I was working on a picture today, however, where auto levels gave my nice orange and yellow colors a greenish tint. So that is where I manually adjust the levels. Basically I want the lightest and darkest points of the histogram (the triangle sliders) to match up with the lightest and darkest points of the graph (so if the graph were to stop on the right, say a centimeter before the end, I might put the right slider a centimeter before the end as well). (This is a bad explanation but I hope it gets across at least a basic idea.) I don't use curves as much but some people prefer that to levels adjustments - I just don't know as much about it.
Why I'm saying all this is because the main problem I see with your shot is that the darks look too dark and muddy and the lights look too light, or washed out. Try playing around with the levels and see if you can get it to look a bit better. (I know this was a morning challenge where a lot of light was probably the point in a shot like this, but maybe this can give you ideas on where to go in the future.)
I hope this helps - PM me if you have any questions! :-) I am glad to see you participating in challenges - I love the seagull shot - and your portfolio shots are interesting as well :-)