First and foremost, an administrator is just a regular user with a few additional tools. An administrator is not to "lead" a community, but rather to make sure that the users stay within the rules. Don't micro-manage everything, but try to create an atmosphere where people can feel comfortable enough. If there is a community, make sure you can place yourself in their shoes. How would they feel if I...? Why would they stay at this wiki? Why is ... allowed or not allowed?
Since, I see this said alot, I'm going to chime in to disagree a bit.
Admins are not regular users with a few additional tools. Admins need to be much more careful because they have these additional tools. They also set an example for other users and moderators. Unlike regular users, admins need to have a regular presence at a wiki, especially if there aren't enough admins or some are known to be absent for good reason (school, vacation, internet problems, etc.). Admins need work on making rules (policies and guidelines), but regular users are not obliged to... they are just supposed to follow them. Admins enforce the rules and need to be able to explain and justify their enforcement actions.
Many a wiki has been damaged or given a bad reputation, by admins who acted like regular users with a few additional tools. Admins should be held to a higher standard.
Feel free to disagree, but try to give some good reasons for your disagreement.
I am not going to disagree with you fully, because there is definitely quite some truth in that. Admins are often (not always) the main or first users someone is in contact with, and they should definitely be some kind of example figure for new users. They also have additional responsibilities (to sum up the rest of that paragraph). So far, definitely agree with you. However, from what I've seen from newer (and often younger) admins is that they've taken up the role as meaning "micro-manager" or even "god". An admin isn't someone who delegates tasks (also due to "regular" users having no to little responsibilities), they don't own wikis, and they definitely aren't someone who can just do what they want "because they have the power". As you said, they need to be the ones who create opportunities to edit, but also the ones who create the policies.
Maybe "first and foremost" were not the right words, but this is why I mentioned the second part of that reply - they are the ones who create a healthy atmosphere, they need to think with others, but they also need to think about the boundaries. To make it very black and white with "collaborator" and "tyrant", the first one could give the wiki a bad reputation if it goes wrong, but the second one could get your rights stripped or could even get you blocked. I'd rather take my chances with the first one.
I meant regular user as in a registered user on the platform, who maybe is interested in editing on the platform, but has mostly been on the wiki for the social features - I think the majority of users of a certain age are included in that - they would have been on the wiki regularly, but you can't expect them to start editing.