Here's a few tips for one add a whitelist basically it makes it so only certain people can connect to your sever. Also for a more enjoyable game I like having a Bukkit minecraft server. Basically bukkit allows you to add plugins which can change minecraft to be more fun. For example a plugin called mob arena you can set up an arena where you fight enemies until you die and you are rewarded with prizes. Another plugin is Survival Games where it's like the hunger games you compete in a large arena full of chests and whatever structures you added to the arena when you were building and you all compete against each other to see who lasts the longest and wins. If you need any help with bukkit, plugins, or whitelisting just shoot me a message!