The following are common methods you will want to call in your front end templates:
craft.wishlist.lists(forUser = true, forceSave = false)#See List Queries. By default, forUser is set to true, ensuring only lists and items that are owned by the current user are shown. Setting this to false will fetch items for any user, so be careful. You can also force a new list to be created in case one hasn't already been created.
craft.wishlist.items()#See Item Queries.
craft.wishlist.item(elementId, listId = null, listType = null)#Fetches the Item for a provided elementId, and if provided, the listId. If not provided, will look at the default list. You can also provide the handle of your listType to check against lists that may not be created yet.
craft.wishlist.getInUserLists(elementId)#Returns true/false whether a provided elementId exists in any lists for the current user (guest, or logged-in user). This can be useful if you have multiple list types, but want to denote if an element exists in any list of the user.