It's a good start! If it were me, I'd have another bridge. Also, consider a cave or two so that a fish may just back in and hide out. You don't have a lot of room, so you'll end up giving one thing up for another, but whatever you choose to do will work out fine. I like the island you've created. To me, those are a must. Even if it's just one.
When my next build finally happens, it's the scape that's going to be the most fun to set up. I haven't had a tank in 12 years. Back then, ya just piled up rock on the back glass and went with it. Maybe an overhang, and a cave or two, but the focus was fitting 2lbs per gallon of rock in a tank. Not a lot of artwork there. So yeah, I'm looking forward to seeing what I can create for a 48x39x25.