I assume when you say "make my own," you mean design the parts templates, correct? Yes; people sometimes design paper models using programs like Powerpoint to make the templates (usually for simpler models). For more complex models, standard practice is to find or create a 3D computer model, then use a program to "unwrap" it, leaving you with 2D templates. I think the program is called Pepakura.
I'm sure someone much more experienced than I will be able to give you more advice.
Good luck!