How can you use your smartphone more efficiently?

We need to stay connected all day, but that causes constant battery (energy) drain.

How can we make our smartphone energy consumption just as smart as our smartphone themselves?

Phones/tablets have a number of tweakable data connectivity settings and battery usage/CPU tuners. Also, WiFi hotspots are popping up everywhere.
Yet all this seems to just add to the confusion as to what type of connectivity drains your battery faster.

Here are some generalizations that may help:

1) Leaving your phone registered/idle on either 2G or 3G should produce similar battery usage. Voice-only mode without much data should produce very similar battery drain.

2) If the 3G signal is poor, or coverage fluctuates, 3G will use much more power while actively transfering data.

3) 2G has better, more consistent power drain when the 3G or 4G coverage is spotty or fluctuating. Use 2G-only mode if the signal is bad, and/or you do not need heavy data usage to increase battery life.

4) 3G has a higher battery drain, and 4G even higher, however, it actually uses less Watts per downloaded Kilobyte compared to 2G. 3G is much better for heavy data usage, and will not use much more battery if the 3G signal is strong. If the signal is poor or fluctuating, however, it may drain your battery as much as twice as fast compared to 2G. Talk time is considerably less than 2G, however, standby drain is about the same. Overall, under typical conditions in suburban areas, you should expect about 2/3 of the 2G battery life.

5) WiFi is more efficient and uses less battery in modern phones than the 4G radio while associated with an access point. It will use less power than 2G if the phone is “smart enough” to power it down while idle. It will use more power while searching for a WiFi signal, however. Another notable exception are some older phones that used inefficient WiFi chips, they’d get warm/hot to the touch just minutes into using WiFi and keep it at high power regardless of network conditions. Generally, WiFi battery usage should be very similar to 2G (unless searching to associate with an AP). It may make sense to turn the WiFi radio off if you only need light data usage.

All this is highly dependent on whether/which radio remains on while the phone is idle or the screen is off, whether you turn off the WiFi when you’re out of range (or the phone is “smart” enough to do it on its own), whether 4G gets turned off automatically when WiFi is on, the strength of the 3G signal, etc.