Hello danna,
I have a 9, so it might be a bit different, but there are a few useful things. I've set my lock key double-press to toggle the torch, letting me use it without having to look at it (and I set long press to camera). (under advanced settings > smart key)
I found the back double and triple tap options often got set off in the car, so I disabled those. (advanced settings > back tap)
I find the gestures on dark screen options very useful, particularly the media controls. (advanced settings > gestures >gestures on dark screen)
There's a few other useful features when you go through all the settings, but those are the main Asus-specific ones that I use.
With the camera, there is a few things there:
You can long-press when focussing on something to get separate focus and exposure settings. It also works just for locking the focus to a specific depth for photos where autofocus doesn't generally work as well.
In the main camera, the shutter button has a few different actions: tap takes a photo, holding takes a video (and then can be dragged up to lock), dragging right takes a burst shot, and dragging up delays by up to 10 seconds (I turned off the led flashing in settings)
For night photos and light trail photos, they turn out a lot better if the phone is somewhere still like a tripod (the phone detects when it is on one and will take a lot longer exposure in night mode)
