Is there any way to create a tag without asking a question? I want to create a tag, and I can't find anyplace where it says 'create tag'. I looked under the 'tags' menu, and I clicked the 'new' button, but I still couldn't find it.
There is no reason to do that. No one will need a tag before it gets used. Searching for it will give an empty result set any ways, so there is really no point. Ask the question and the tag shall be created! You'll also get a better idea of what tag you need and what it means to you.
Tags are implicitly created when they are first used - you can ask or edit an existing question to reference a tag that doesn't yet exist, and that will create it.
Don't forget though that the wikis for tags are about what the term means for this site, and not about creating a general photographic encyclopaedia.