Honestly, it really just doesn't look like enough light to me at all. Only the middle of the tank looks like it's getting any light at all. Here would be my recommendations:
1.) Up the lighting. You can get a Fluval PCL-13 on Amazon for $25. That's going to be a LOT of light for such a small tank, but if you really watch the photo period, dose Flourish Excel, and maybe have the light raised 6 inches from the top of the tank it will be fine.
2.) Get rid of the substrate. I would use Fluval Stratum or Seachem Flourite Black Sand instead.
3.) Use the rock that you have in there to add some depth to the substrate. You can do some really cool slopes from the back to the front of the tank by using a rock to hold the substrate up a few inches above the front in the rear.
4.) Keep tall plants to the back of the tank and carpeting/short plants to the front of the tank. This will make sure it doesn't just turn into a mess that you can't see through.