My iphone 6s plus battery percentage seems to go down quite rapidly. How can I slow down this percentage drop?

My iphone 6s plus battery percentage seems to go down quite rapidly. How can I slow down this percentage drop? AT 7:00 AM this morning it was at 100% now it's at 32%. Seems like a lot of usage. Background apps are disabled. I've tried to turn off everything that I feel is not necessary but seems that battery % still seems to drop quite quickly.