Try to take the battery out of the laptop when not in use. Some laptop batteries are easily removable, while others aren't - certain manufacturers make it impossible to remove the Apple battery at all without opening the case in a way that voids the warranty. If this is the case with your laptop, just leave the battery in place.

Keep the laptop and the battery at a comfortable temperature. Exposure to high heat or extreme cold can damage the battery, not to mention the laptop.

The vast majority of modern laptops use lithium-ion (LI or Li-ion) batteries, which undergo less stress and last longer when not completely discharged. Ignore outdated advice (based on older battery technologies) to fully drain the battery with each use, and only use the battery as necessary.

Turn down the brightness of your screen. The screen's backlight is one of the major sources of power consumption - if you keep it at the lowest level you can comfortably use in the current light, your battery  will last significantly longer.

Turn off or mute the speakers on the laptop - use headphones if necessary to minimize power consumption for sound.

Do not plug in unnecessary external hard drives, speakers, USB devices or other hardware when the battery is in use.

Close all unnecessary programs and turn off scheduled tasks like virus scans to minimize disk and processor usage and save battery life.

Limit use of games and videos. Graphic and sound intensive programs drain the battery faster, especially on laptops with dedicated graphics and sound cards.

Change your laptop's power-saving options for maximum conservation. On Windows, you can change the settings of the Power Options in the Control Panel so the hard drive and screen turn off after a few minutes of non-use. On Macs, you can access the Energy Saver pane in the System Preferences application to achieve similar results.

Copy CD or DVD information to the hard drive. The laptop uses less power if you run such programs from the hard drive rather than use the CD/DVD optical drive.

Make sure you re-enable any scheduled tasks like virus scans when the computer is next plugged in.

Be careful when working with power cords and  batteries. Follow all instructions from your laptop's manufacturer to avoid possible damage to your device or yourself.