Most important, don't leave dead batteries dead, it will reduce their life. Keep them charged and ready to go for next time. Don't store batteries in extreme cold or heat, (like in the car on a hot summer day or cold winter night). If you have an option of charging fast vs. charging slow, choose slow for extended life and fast only for convenience. Cycle multiple batteries if you have the option to. If you need to store batteries long term, don't leave them fully charged but not empty either, (3.6v if you have a way to test it, 2 bars if not). Let batteries cool 5 minutes after use before charging and after charging before use.