Also make sure auto stand by is at the lowest setting. Which is 1 min.
You'll find this in power save settings under settings.
Another thing too is the refresh live area screen. Especially this as the lil' blue home button stays blinking even on sleep mode as a reminder to new messages or whatever other tid bit of info gets displayed on screen.
You can turn this off in auto start settings. This blue light is a major battery drainer. As ones vita can be ignored for awhile while the blinking continues unnecessarily.
Welcome to vita land.
Like what people are saying, put you Vita in Airplane mode. You can still connect to Wifi (after you turn wifi back on but leave airplane mode on as well)
So the 3G will be off but you will still have access to wifi.
Welcome to the "club" ...!
I have the same model too. All the recommendations mentioned are good to follow. Also, though, keep an official charge cord handy. Buying an extra one makes it a lot nicer to deal with.
With the official charge cord you can play and charge at the same time.