I'm really, really new to the modding scene, or rather new to making anything resembling a mod. I want to take a piece of standard clothing (a shirt and some pants), and make versions that are read by the game as armor, complete with an armor rating and all that. I looked for some topics on this specific matter and couldn't find any, so I thought it would help to make a topic myself and ask.

I had a couple of ideas how I might go about to make it, but none worked (I had wrongly assumed that apparel could just be given an armor rating in the Construction Set and be done with it). So, how can I do this? Any help would be really appreciated.

No problem at all, you can use any armor as template to create another (armor) item, change the fields "NameID" and "name" at your leisure, all the values you want, and place the names of the mesh and icon of your choose cloth, if they are the same type, says upper body, or glove, or... you just need to save the new item and use it as you see fit.

Never tried this, but I think it works

Anyway, Why not just give the cloth a shield enchantment? it is almost the same for gaming purposes unless you are trying to enhance your armorer skill (just care to make a clone with new ID, so to avoid changing all equal items in game)

I still seem to be having some trouble. I'm doing what you said, but i can't find the right NIF file. I find the female version, but nothing for the male. The file on the Forester's Shirt (the shirt I want to make armor out of ) directs to mcshirtforester\m\shirt.nif, but when I go to reference it for the armor, the male folder \m\ doesn't come up. I only find \f\, and I'm pretty sure I don't want my male character with a feminine build.

Well, I'd give it a shield enchantment but I want to be able to give it other enchantments too. The character I'm using isn't really a magic user, so I want to be able to have this specific shirt as an armor. I also can't exactly afford the enchanting costs at the moment, so I can't enchant it with anything worthwhile unless I by chance find a really good sigil stone.