to answer this question we would need to know what phone? what OS? what apps? how do you typically use your phone? do you have wifi? strong signal? carrier signal good? indoors or out when it drains? BT on?
2 months has passed to update the os..but still battery draing quickly?!
10.3.2.2474
Check your device usage and the individual app use. There are likely some apps which are system hogs. You may need to remove some of them if you don't use them frequently.
The Priv has been updated since release. You may want to consider doing so.