I am a high school student with a question, and I am not entirely sure this is the right place to voice it. I often encounter situations where I want to use a word to describe a specific situation I'm writing about and then discover I have actually just made the word up. For example, and this is one I'm particularly upset about, in wanting to say that something that was once abnormal is now expected, I created the word 'deanamolize'. This is through adding -ize to indicate that anomaly is being changed, and de- to say that it's no longer an anomaly. To start, if this was hypothetically real, is it even morphologically correct? And then, if the former is true, is there a way to introduce the word into actuality? Thank you for your time!
I assume you mis-spelt it to mean "deanomalize" (not "deanamolize"). This follows English word formation rules, and is perfectly fine. Without having encountered this word before, I can understand what it means, and if I use it, other people will also be able to get what I mean.
What makes this a 'proper' word is -- as mentioned by others -- not a formal process. There is no committee where you an submit your word for it to be accepted. Though in a way there is: the editors of dictionaries have a gatekeeper-like function in that they decide if something is added to a dictionary and thus gets a "seal of approval".
But a word can exist outside of a dictionary. Words spread through usage, and if people find your new word useful (and can understand what it means), and they start using it themselves, then it might eventually become a 'dictionary word'. There are loads of idiosyncratic words, slang words used in small groups, etc which never spread outside the group, but in a way they are still words.
So if you want to promote your new word, keep using it. Either it will be adopted by other speakers (if there is a genuine need for it), or it will not spread because it is too niche, or there are already other words that express the same meaning.
Language doesn't gain words through some formalized process. Most linguists would say that a string-of-sounds-which-could-potentially-be-a-word (let's call this a pseudo-word for short) is "officially" a word when "enough" people use it to communicate with each other (you know, like most words).
"Enough" is subjective. Some linguists would say you only need one user of a pseudo-word for it to be a word. I think most would agree that if everyone in a small town used a pseudo-word, it's a word (at least in that regional dialect of the language).
As you're probably one of very few people who have ever used the pseudo-word "deanamolize", I would say it's not a word. This doesn't mean you're wrong for saying it, or that you can't use it.
(This doesn't mean that you should continue to use it if someone expresses annoyance with you using it. This isn't coming from a linguistics point of view, but a not-being-obnoxious point of view.)
The way you would "make" it a real word is to normalize its usage, so that "enough" people accept it.
One reason you may find this task difficult is that there's a much more commonly-used word which means something pretty similar, which I used in the previous sentence.