I like the composition. I'm not so sure it couldn't be sharper though, it looks like you/your camera focused on the trees instead of the moon. If you have a tripod you could use that to maybe slow your shutter speed and thus lower your ISO to reduce the noise a bit and/or stop down the lens to get both the moon and trees in focus if you wish.
Frequency, that's weird from the way you explained it. You focused on the Moon, yet it's not in focus, but the Palm leaves are. It's still a really nice composition. Next time you'll nail it for sure.
You definatley did focus on the trees but in my eyes that really is not a bad thing. I love the blue, it gives a coldness to it. If you really wanted to mess around with the composition you could move the moon up and to the left...just to see what it looks like but thats just my oppinion