There are a number of good articles available, perhaps this one will help?
http://batteryuniversity.com/learn/a...d_acid_battery
However I'll sum it up to say:
1) Fully charge the battery and take it off the charger.
2) Repeat step one every three to four months.
3) When driving/practicing don't drive you battery down to zero charge... change it and charge it before you fully deplete it.
Put your team name and the date on batteries when you receive them. Use your newest batteries for competition (only!) use the older batteries for practice and public performances.
Well, okay... test the new batteries once or twice before the competition, and one year-old batteries (or even older) are good for competition if you take care of them.
Jason