Yes I have tons of tips! I have made a Mini-Games server that closed down.
1.Always use the Permissionsex plugin don't use GroupManager! PEX is much more complex but more better.
2.Don't be crazy advertising for donations let the donaters come to you.
3.Try to use classic games like a plugin for a specific mini-game like
http://dev.bukkit.org/bukkit-plugins/survival-games/ 4.Watch a lot of YouTube videos they can help!
5.Don't get plugins that you don't need.
6.Hire staff that are true to you.
7.Make YouTube videos
8.Add votifier.
9.By skulls I don't understand? if you mean player heads it is a plugin you can download its called PlayerHeads
10.You need a great builder!
11.If you want to make a simple spleef game get the Minigames plugin and watch a video.