Japanese clothing is almost all based on a very simple pattern of rectangles. While any given garment has a characteristic width, in general Japanese fabric is much narrower than European, and the construction of clothing reflects this: it takes about 4 widths to adequately cover an average person.
The basic Japanese garments are the kosode and hakama, both of which are worn, with monor variations, by men and women alike. The kosode is a robe-like garment which overlaps in front (always left over right, unless the wearer is dead or expects to be shortly); hakama are variously described as a divided skirt or very full pants. The kosode as underwear is invariably white, though when worn as a visible garment it may be any color so long as it is lighter than the hakama. Men's hakama are often black, while women's are often red. Patterns for these two garments may be found here
Over the kosode and hakama one may wear any number of other robes; this practice reached its full flower in the Heian period.
For men's costuming, there can be no better source than Sengoku Daimyo.