Kimela,
I forgot to mention a couple of things while I was typing on the surface interval. People love the TG6 for macro, so if you don't like your macro shots my first guess would be the fact that you are using a light as opposed to a strobe. Don't know, but that would be a guess. Second point I was going to make is that I haven't been doing this for long at all. I basically started fooling around with non-GoPro cameras this summer (I carried a GoPro in my pocket starting last fall). I had a camera I had fooled around with on a couple of dozen dives 10 years ago, but hadn't touched it until this July. Bought the Sony camera in August.
Bottom line is that I am pretty certain I am not in the top dozen photographers in the Cozumel chatroom (and not in top 100 on scubaboard), so I would place the opinions of jlyle or Cicopo or one of the more experienced photographers way above mine. I get a fair number of decent pictures because I am in the water quite a bit, not because of skill or my deep knowledge of photography. I try to answer photography questions when asked, but I am definitely not an expert.
EDIT: One thing I forgot to mention is that I do use Adobe Lightroom to edit photos, that may be a decent part of the differences you are seeing. Obviously no photo editing software will fix focus, composition etc, but it can help fix a lot of issues you may run into underwater (backscatter, white balance off, under/over exposed, photo looks better cropped etc). I am sure photo purists prefer 100% of the original image with no fixes whatsoever, but shooting underwater in current that is asking a lot. Just to be clear, I am not doing artistic double exposures, cutting and pasting from one photo to another etc--I am just trying to fix what I didn't get right underwater. As I had mentioned, the picture of the 4 eagle rays was really awful as shot since I definitely wasn't set up for low light from a distance--probably had to make 20 different adjustments to fix what I had screwed up underwater. If it had been a picture of 1 eagle ray and not 4 of I would have just deleted it.