I have never had a problem with battery life.
I turn it off overnight, and turn it on around 6:30 and I get notifications, and make around 2 quick phone calls a day with it. I may take the odd picture. I have the sound and screen brightness at level 2.
By late evening the watch can be at 70%. I usually keep my phone near me, although sometimes when at home the phone is in the kitchen and i wander around the house. I don;t know if distance can drain the battery.
I am sorry this may not be much help, but I thought I would share my experience with you- as 10% seems quite bad - could it be you are knockinghte watch and activating the camera and it is running for a while with out you knowing?