Just because 3 people asked me this today only, I'm posting. Thought this might be useful for some.
Simple steps:
1. Open the battery compartment, and read the information on it.
2. If it says it's made of
Li-Ion or Ni-Mh: You want to keep it plugged in as much as you can; preventing it from going below 75% charge.
Why? Li-Ion/Ni-Mh are designed so that it carries a certain number of charge cycles. As the number of drain-charge cycles (after taking some wear) go up, its battery lifetime will be shortened significantly.
So, plug your laptops, cellphones, and whatever it is whenever possible (NiMh or LiIon!)... This helps SIGNIFICANTLY.
For more info:
http://www.pcmag.com/article2/0,1895,1902204,00.asp