OK some suggestions for you.
Firstly the problem is all the cables go out of the power supply and behind the board tray through the wrong grommet. I see you have put one cable through the grommet which is closest to the PSU, see if you can get more cables through that grommet. That will tidy up the look at the bottom a lot.
Not sure why you have that USB 3.0 mounted like that in the case, would be best to either remove it or see you can mount the USB 3.0 expansion port the other way round so it's like your hard drives. I thought those 3.5" USB ports went in the front of the case anyway where a floppy drive would traditionally be installed?
I see you've got some SATA or Molex power cables hanging around at the bottom of the case by your GTX 670, just put those behind the motherboard tray too. You should have enough room to hide them away.
Not sure what that cable is which is hanging around on top of your graphics card, I think they're molex power lines powering your LED strips? It would be best to take out the LED strip and then route it start at the bottom of the hard drive caddy, because then you can route a molex cable underneath the hard drive caddy and then hide it easily. You get what I mean?
I also notice your graphics card is in the bottom or middle slot? Why? It would probably run faster if it were mounted in the top PCI Express 3.0 slot. Does your CPU cooler get in the way if you mount it up there? If you mount the card in the higher slot, you can re-route the power cables to go through a grommet which is closer to the GPU.
I wish I could say "pass it here and I'll do it myself" but it's kinda hard when I'm in the UK in you're in Los Angeles.
Hopefully I've given you some help. Good luck.
