Once over the hurdles that have led you to having a home page, you may benefit from the collective wisdom and experience of other Wikians even if you know your subject inside out and can't wait to start writing. Tips here are for:
On the "About" page of your new wiki, add a mission statement. (You should have an outline of one already, prepared when applying for the Wikia.)
This is your vision of what the wiki will be, and should explain to people what they can expect to find on the wiki. You should list the aims and goals of the wiki on this page, and explain who your target audience is. Explain to people how they can become part of the wiki.
You will need to start the content creation on your wiki by "seed posting". Be prepared to devote a lot of time to this in the early days before a community develops on your wiki.
It takes time. In the first two weeks, friends will create their home-pages and leave a few kind words for you on the wiki. Be prepared to spend three, four or more months adding content all by yourself. You will be contributing at least 95% if not 98% of all content. That requires about 1-2 years of 1-2 hours of daily work.
Do not kid yourself. Only a dozen people will actively contribute to the wiki in the beginnings. They write the remaining 2-5% of the content. You might start to see a change after a year or two and 1000 or 2000 pages written.
Strive to stay on topic to your wiki rather than adding irrelevant content. Having a clear mission statement can help with this.
A favicon or favourites icon, can be uploaded to Wikia to give a personalized icon associated with your Wikia. These will be shown in the browser's address bar, next to the site's name in lists of bookmarks, and, in tabbed browsers, next to the page's title. Just upload a .ico file to "Image:Favicon.ico" to add one to your Wikia. It is recommended that an admin protect the upload. See Creatures:Image:Favicon.ico for an example of a Wikia using a personalized favicon.
Add a search logo
An image can be added above the search box in the sidebar by uploading a file called "Search_logo.png". If a logo is added, the image will link to the Central Wikia.
Edit the interface
The interface can be edited using the MediaWiki namespace. See Help:navigation and the MediaWiki namespace help category for help with various MediaWiki namespace templates. It is recommended that you keep the default basic structure so users familiar with other MediaWiki sites can find their way around easily. You need admin level rights to edit the interface. For more information about configuring your wiki through the MediaWiki namespace, see wiki configuration.
Change the style sheet
The overall look of the site can be changed by editing the page at MediaWiki:Monobook.css for the wiki. Individual colour schemes and other changes can be made with this style sheet. See Wikia custom skins for examples of Wikia that have made these changes.
If you want to develop a community, you will need to tell people about your wiki. Explain to people who may be interested in the topic area that the wiki is a common effort. Be welcoming to visitors and encourage them to become part of the wiki.
You may want to advertise for new users on relevant mailing lists, and through your own contacts. However, be careful that your messages do not come across as spam.
For wikis about local areas, you can make a press release, or send a notice about the wiki, to your local newspapers and residents groups.
At some point, you will need rules for your wiki. Keep these simple at first, and expand as you need them. For example, there is little point trying to create rules against a certain number of reverts years before anyone gets in an edit war. The rules should grow with the wiki, and be developed by the community over time. Applying too many policies is a common mistake.