4. Double Tap to Wake
This is one very comfortable, quick and faster way i found to get access to new notifications on my phone when it is kept on table. Unfortunately, it is only on LG, and very few other devices. For the rest of the device, you atleast need to tap/press atleast one physical key. However, it was seen the Marshmallow Dev previews, but again, eliminated in the final release. Dont know why. We would like to see it in the next, Android N update.
5. Advanced Power Menu
Well, this sounds very small but, trust me, it is very useful offering quick access to important options. For this particular part, i found Custom ROMS very effective. Wish to seem them in Android native OS as well.