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Not making these 'subtle' advertisements would be a good start. Buy hosted tab, get online together with a few friends (nobody joins an empty server) and tell people you know to come and invite their friends.

And also, you don't need admins. You don't have any players yet, so there's nothing to administrate and you can simply do it by yourself. If you get so many players that you can't handle it alone, that would be the time to look for admins.