How to increase smart phone battery life

When you first use your mobile phone, charge the phone to 100% and then use it till the battery discharges completely.
Switch off wi fi, bluetooth, GPS when not in use. This can give up to 40% extra battery life.
Most of the phones come with Lithium-ion batteries, try and keep it charged north of 50%. The batteries don't have 'memory effect' anymore so it pays to keep it fully charged to increase its life.
Keep your phone / battery away from direct heat or sunlight.
Avoid wireless charging as the inductive charging creates heat which can damage the battery.
As much as possible, try and use the original charger for the phone / tablet.
Use powered USB hub to charge phone / tablet.
While charging your phone, try and charge it in flight mode, it charges 50% faster.