Without sounding critical,
what look are you going for?
Are you going for an "underwater ruins" type of look,
or something a little more natural?
In my opinion, there's too much rock for a natural tank.
I'd try to scale it down to one side, and stick to a common
color set (ie, be rid of the reddish browns)
If this is an "underwater city ruins" type of tank, again
I'd be rid of a bit of the rock. Maybe 6-8 pieces from
the right side? Then I'd add some Java Moss, Crypts
and a few java ferns in between the rocks. Maybe
a heavier stemmed plant that would cascade down the rocks
(kind of like Ivy).
As for the substrate, I think it looks great. I'd add a lot of
ground cover (I'm partial to Dwarf Hairgrass, myself although
some Riccia could look good if you can stand the maintenence).
I'd also add a plant to the left side. Something like an Amazon
sword or some Wisteria. Scratch the amazon sword, actually.
Something with smaller leaves (a little bushier) would look
Overall, I think you've got a good medium to work with. Your
tank could end up looking great once it's established (with a few