Safeguard your laptop battery from excessive heat and extreme cold. Ideal would be room temperature.
Always place your laptop on a flat, stable surface and make ensure the cooling vents are clear and unhindered.
For Laptops with a removable battery, take it out and clean the metal contacts at either side once every couple of months with a dry cloth and alcohol solution.
For a long and healthy battery life in your laptop, avoid leaving it constantly charged. Ideal ways would be to drain the laptop’s battery to around 40-60 % at least once a week & fully discharge it and recharge it once or twice, every year.
Battery life can also be improved by altering laptop’s power saving settings. Look out for battery management utility provided by laptop manufacturer and make use of it.