[Endoperez]

You don't want to use a good spell or option. You want to use the best one.

This is the rule of competitive multiplayer. I can't offer any good examples, but you'll see it in action once you try out few games, e.g. blitzes in the #dominions irc channel. You can copy and/or adapt experienced players' tactics, or use your own. If you use your own, even though they aren't bad, they probably won't be enough to guarantee your win. I had lots of fun trying out my own subpar strategies when I had time to try some blitzing, though.