Next, this is the 'channel' I decided to use for running all my cable, just at the empty space next to the motherboard. Cable-tied all neatly and used the bracket included with my centurion 5 to stick it to the casing. Wish they gave more of those brackets. The cables are very close to the motherboard tray of the casing, so it doesn't really block airflow and makes it quite neat.
The sata connector is right next to my hdd, so very close and the sata cable I had was quite long, so decided to coil the cable to make it shorter instead of hiding it. You can try this too if your hdd is next to the connector. Just take a chopstick and coil the sata cable around it slowly.
Ok, cables for casing like power and reset button, power and hdd led just cable-tied them neatly and made the cable straight by hiding the excess at the front part of the casing, away from the view through the side window.
Finally, simple way to hide cables for fans. Just tuck them neatly around the fan, then run it up towards the PSU. Can't be seen through side window.
Ok, that's all I have! Hope it helps and hope you guys can give some suggestions too.