Agreed. Set out your grammar, then think of words.
The hardest part about Latin for me was the grammar - there are literally (Using the word in the correct sense here) about 15 ways to say the world 'Table' depending on who is saying it, to whom they are saying it, which tense it is in and in what context it is said in.
While that might seem a bit crazy, it makes much more sense than English when you wrap your head around it (think of the saying "i before e, except after c", and how often that is incorrect - weird, ancient, society, beige etc).
So maybe you set it out that you have 3 categories of words - names, descriptions and actions. Your names can be whatever they need to be for characters and weapons and buildings etc. Your descriptions always end with an "ipo" if addressed to someone, and "iuo" if describing something inanimate. (And so on and so forth). From those rules, construct your words.
I hope this makes sense, and maybe it helps?
