for me, lower the screen brightness, turn off when not in use...... never ever leave charger in phone or laptop when battery is charged 100%...little things like this keep a battery lasting and performing
james

Newer laptops, tablets and cell phones no longer charge the battery just because they are plugged in.

It is hard to find a battery pack that does not have power management chips built in.

I read the part about using the charger that came with the device - but I do not think that USB powered devices are that picky. One example that I'll cite where using the original charger did more harm than good is my cell phone. The original charger will charge the phone much faster than using a USB jack from a computer or the auto's dashboard. Unfortunately, combine the heat from a fast charge with the heat of the GPS antenna and the heat from the cell antenna on max due to being far from a tower and the phone overheated/shutdown. I had an air vent cooling the phone, but it was not enough. I don't use the original charger on that phone any more while on trips.

iPhone, overheat/shutdown... I've had this happen too
Phone in car kit charging, gps on, car kit holder sits near windscreen.

now if i put a piece of paper over the phone, so that it does get direct sun, the paper shades it, it's ok.

I didn't think the Li-Ion batteries had a memory effect as like the old ni-cad's.
and also the charging circuits these days are a lot better

Some think it best to let the battery...
...drop 10%
...then charge
...then drop again
...then charge again
~~~~
Always keep things moving.

Others are so against that theory that they developed power management software for rooted androids to prevent that constant cycling that the manufacture built in.

Some Dell laptops have a variable charge pattern. It changes how the batteries are charged based on past usage patterns and how long it is plugged in. Its quite nice.

I had a salesman tell me that I would ruin my cell phone by plugging it into a USB adapter that put out 5 volts at 2 amps. He claimed that my phone was only rated at 0.5 amps. I thanked him for his concern and bought the adapter anyway. Of course, the phone never draws more current than the power management chip allows. I wanted the 2 amp rating for other devices that can make use of it.

Step down transformer + trickle charger

You have nothing to fear from a usb charger that is rated for 5.1VDC. You can use it to charge any device that claims it can be charged via USB. The USB2.0 "on the go" spec sets the charger's output range from 4.75 to 5.25 volts. Source (PDF).

The device receiving the charge should have a power management chip that can handle around 6VDC input.