Layers..
A medieval person wears.. skin - underwear - armor/cloths - equipment - cloak
Skin/hair is given.
Underwear.. certainly is what DaveG meant with cloths..
Usually you don't wear a pullover above a heavy armor, so either armor or nice pants. One usually also doesn't wear thick cloths under armor as it simply can get _very_ hot inside an armor. So only thin underwear or clothing under armor if anything.
Equipment and cloak is nothing complicated.
Problem with clothing: you can wear multiple shirts or pants or cloaks, if they aren't too thick.
Other problem is that you can't get out of your T-shirt while wearing an armor.
After concidering a few ideas, my favourite one is to have a thickness indicator for each clothing.
Your inventory window shows a field that indicates the thickness of the stuff you are wearing on specific parts of your body.
Now you can wear a thin shirt (1), chainmail (3), plate armor (5) and a cloak (1) like that:
----
| cloak
| plate armor
| plate armor
| plate armor
| plate armor
| plate armor
| chainmail
| chainmail
| chainmail
| shirt
----
To see a specific item you are wearing, point with the mouse on it.
To increase the field, train strength and agility.
Why that system? Because it allows complex clothing without being too complicated, it also allows to wear multiple clothings of the same kind (two or more shirts or cloaks).
For simplicity of the system (and because I love realism) one could only change the clothing that is on top of the stack (that would be the cloak in this case).
Add a field to the items that say which layer they are and only allow items of a specific layer over another. Items of the same layer can be worn in arbitrary order.
Simple and effective
